| ❗ Important Note |
|---|
This is the second test chip from the Chipalooza challenge 2024. 14 designs made it on the September tapeout, although many of those were Efabless designs filling in gaps for IP not provided through the Chipalooza challenge.
The projects on this tapeout and their source URLs are as follows:
1. Power-on-reset
sky130_sw_ip__bgrref_por
https://github.com/fossi-foundation/sky130_sw_ip__bgrref_por (forked)
https://github.com/openicdesign/sky130_sw_ip__bgrref_por
Stephen Wu
2. Ultra-low-power comparator
sky130_icrg_ip__ulpcomp
https://github.com/fossi-foundation/sky130_icrg_ip__ulpcomp (forked)
https://github.com/JYSquare2/sky130_ef_ip__ulpcomp
ICRG (Lee Jun Yan and team)
3. MOSFET voltage reference
sky130_ak_ip__cmos_vref
https://github.com/fossi-foundation/sky130_ak_ip__cmos_vref (forked)
https://gihub.com/adankvitschal/sky130_ak_ip__cmos_vref
Adan Kvitschal
4. LDO
sky130_am_ip__ldo_01v8
https://github.com/fossi-foundation/sky130_am_ip__ldo_01v8 (forked)
https://github.com/AlexMenu/sky130_am_ip__ldo_01v8
Alexandre Menu
5. Instrumentation amplifier
sky130_pa_ip__instramp
https://github.com/fossi-foundation/sky130_pa_ip__instramp
Phil Allen
6. Audio sigma-delta ADC output driver
sky130_iic_ip__audiodac_v1
https://github.com/fossi-foundation/sky130_iic_ip__audiodac_v1 (forked)
https://github.com/iic-jku/iic-audiodac-v1
IIC-JKU (Harald Pretl)
7. 16MHz R-C oscillator
sky130_ef_ip__rc_osc_16M
https://github.com/RTimothyEdwards/sky130_ef_ip__rc_osc_16M
Tim Edwards/Open Circuit Design
8. 500MHz R-C oscillator
sky130_ef_ip__rc_osc_500k
https://github.com/RTimothyEdwards/sky130_ef_ip__rc_osc_500k
Tim Edwards/Open Circuit Design
9. 8-bit rheostat
sky130_ef_ip__rheostat_8bit
https://github.com/RTimothyEdwards/sky130_ef_ip__rheostat_8bit
Tim Edwards/Open Circuit Design
10. 8-bit IDAC
sky130_ef_ip__biasgen
https://github.com/RTimothyEdwards/sky130_ef_ip__biasgen
Tim Edwards/Open Circuit Design
11. 8-bit RDAC
sky130_ef_ip__rdac3v_8bit
https://github.com/RTimothyEdwards/sky130_ef_ip__rdac3v_8bit
Tim Edwards/Open Circuit Design
12. Comparator for ADC
sky130_ef_ip__ccomp3v
https://github.com/RTimothyEdwards/sky130_ef_ip__ccomp3v
Tim Edwards/Open Circuit Design
13. Sample-and-hold
sky130_ef_ip__samplehold
https://github.com/RTimothyEdwards/sky130_ef_ip__samplehold
Tim Edwards/Open Circuit Design
14. 12-bit CDAC
sky130_ef_ip__cdac3v_12bit
https://github.com/RTimothyEdwards/sky130_ef_ip__cdac3v_12bit
Tim Edwards/Open Circuit Design
(Documentation, including test instructions, still needs to be completed)
:---: | :---
Building:
Get the dependencies above by doing "make get_ip_blocks" in the top level directory. This will clone all of the IP blocks from various github repository sources into the "dependencies" directory.
The test chip is generated in magic by running magic in the mag/ directory and issuing the command "source construct_testchip.tcl".
Verifying:
In the top level directory, do "make run-precheck". This requires at least setting environment variables PDK_ROOT, PDK, and PRECHECK_ROOT. If the PDK is installed with open_pdks, then PRECHECK_ROOT can be set to open_pdks/sources/precheck_sky130.
Testing:
All projects are connected either to the logic analyzer (256 I/O bits) or the GPIO pins. Generally speaking, static control bits (enable and trim, for example) are logic analyzer outputs. Dynamic digital bits are routed to GPIO digital outputs, while analog I/O are routed to the analog connections of the GPIO. Each GPIO will need to be configured for digital input, digital output, or analog operation by the program running the test. Because the number of digital outputs exceeds the 128-bit width of the logic analyzer, both "la_data_in" and "la_oenb" lines (which are effectively just additional output bits) have been used. But note that for each index, the "la_oenb" pin, when set to zero, forces the corresponding "la_data_in" line to zero, so it is important to make sure that no single IP block is controlled by both "la_oenb" and "la_data_in" of the same index, or else some configuration settings will be impossible to reach.
Unlike the first test chip, this one has a standardized set of multiplexers on the GPIO analog pins, allowing each GPIO pin to access one of two internal analog signals (otherwise, there would not be enough GPIO pins to accommodate all of the test points needed for every analog block). Each multiplexer consists of two isolated switches, each with two control bits, one of which makes the connection and the other of which grounds the center. These bits should never both be enabled (value 1) at the same time; otherwise, the analog signal gets shorted to ground. These are not, strictly speaking, multiplexers; they are two independent switches connected to the same pin. For that reason, both switches should not be enabled at the same time. In the list of analog blocks and their control signals, below, both the controls for the output of the block in question, and the controls for the other analog block connected to the same GPIO.
Each power supply is routed through gated power pFETs so each project can be powered individually. Each power supply connection internally is routed to a bare analog pin for monitoring the supply voltage of the project, for 11 of the 14 projects (because only 11 bare-analog pins are available). Be aware that these are ESD-sensitive points!
Project circuit blocks are described below, starting at the top left corner of the chip and working counterclockwise around the chip perimeter.
8-bit IDAC (Tim Edwards) Enable: la_oenb[69] Bias: Internally self-biased when Reference select = 0 Bias: (vbg) gpio_analog[17] (pin GPIO 35) set externally to 1.2V nominal when Reference select = 1 (Shared with LDO vref_ext and CDAC Vref) Reference select: la_data_in[35] (0 = internal self-bias, 1 = external bias) Upstream analog power supply: vdda2/vssa2 Upstream digital power supply: vccd2/vssd2 Power supply monitor: (none) Power supply enable: la_data_in[47] Digital input: 8-bit value vector is: la_data_in[31], la_oenb[65], la_data_in[32], la_oenb[66], la_data_in[33], la_oenb[67], la_data_in[34], la_oenb[68], Analog output: source out = gpio_noesd[7] (pin GPIO 25) when la_data_in[18] = 0 (no ground shunt) la_oenb[39] = 1 (connect channel) la_data_in[19] = 1 (ground shunt on other channel) la_oenb[40] = 0 (disconnect other channel) sink out = gpio_noesd[8] (pin GPIO 26) when la_data_in[16] = 0 (no ground shunt) la_oenb[37] = 1 (connect channel) la_data_in[17] = 1 (ground shunt on other channel) la_oenb[38] = 0 (disconnect other channel) Analog input: IDAC reference trim: gpio_noesd[10] (pin GPIO 28) when la_data_in[12] = 0 (no ground shunt) la_oenb[33] = 1 (connect channel) la_data_in[13] = 1 (ground shunt on other channel) la_oenb[34] = 0 (disconnect other channel)
LDO (Alexandre Menu)
Enable: la_oenb[64] Bias: Internally self-biased when Reference select = 0 Bias: gpio_analog[17] (pin GPIO 35) set externally to 1.2V nominal when Reference select = 1 (Shared with IDAC vbg and CDAC Vref) Reference select: la_data_in[30] (0 = internal self-bias, 1 = external bias) Upstream analog power supply: vdda2/vssa2 Upstream digital power supply: vccd2/vssd2 Power supply monitor: io_analog[10] (pin GPIO 24) Power supply enable: la_data_in[46]
Analog output: voltage out = gpio_noesd[9] (pin GPIO 27) when la_data_in[14] = 0 (no ground shunt) la_oenb[35] = 1 (connect channel) la_data_in[15] = 1 (ground shunt on other channel) la_oenb[36] = 0 (disconnect other channel)
MOSFET voltage reference (Adan Kvitschal)
Enable: la_oenb[61] Upstream analog power supply: vccd2/vssd2 (note this is a 1.8V supply) Upstream digital power supply: vccd2/vssd2 Power supply monitor: io_analog[9] (pin GPIO 23) Power supply enable: la_data_in[45] Trim: la_data_in[28], la_oenb[62], la_data_in[29], la_oenb[63] Analog outputs: vbg reference out = gpio_noesd[8] (pin GPIO 26) when la_data_in[17] = 0 (no ground shunt) la_oenb[38] = 1 (connect channel) la_data_in[16] = 1 (ground shunt on other channel) la_oenb[37] = 0 (disconnect other channel) vbgsc reference out = gpio_noesd[11] (pin GPIO 29) when la_data_in[11] = 0 (no ground shunt) la_oenb[32] = 1 (connect channel) la_data_in[10] = 1 (ground shunt on other channel) la_oenb[31] = 0 (disconnect other channel) vbgtg reference out = gpio_noesd[12] (pin GPIO 30) when la_data_in[9] = 0 (no ground shunt) la_oenb[30] = 1 (connect channel) la_data_in[8] = 1 (ground shunt on other channel) la_oenb[29] = 0 (disconnect other channel) vptat reference out = gpio_noesd[7] (pin GPIO 25) when la_data_in[19] = 0 (no ground shunt) la_oenb[40] = 1 (connect channel) la_data_in[18] = 1 (ground shunt on other channel) la_oenb[39] = 0 (disconnect other channel)
Comparator for ADC (Tim Edwards)
Enable: la_data_in[27] Upstream analog power supply: vdda2/vssa2 Upstream digital power supply: vccd2/vssd2 Power supply monitor: io_analog[8] (pin GPIO 22) Power supply enable: la_data_in[44] Analog output: io_out[17] (pin GPIO 28) Analog inputs: in positive = gpio_noesd[11] (pin GPIO 29) when la_data_in[10] = 0 (no ground shunt) la_oenb[31] = 1 (connect channel) la_data_in[11] = 1 (ground shunt on other channel) la_oenb[32] = 0 (disconnect other channel) in negative = gpio_noesd[12] (pin GPIO 30) when la_data_in[8] = 0 (no ground shunt) la_oenb[29] = 1 (connect channel) la_data_in[9] = 1 (ground shunt on other channel) la_oenb[30] = 0 (disconnect other channel) (This pin shared with the CDAC VCM pin)
12-bit CDAC (Tim Edwards)
Enable: N/A Upstream analog power supply: vdda2/vssa2 Upstream digital power supply: vccd2/vssd2 Power supply monitor: io_analog[7] (pin GPIO 21) Power supply enable: la_data_in[43] Analog inputs: reference high = gpio_noesd[10] (pin GPIO 28) when la_data_in[13] = 0 (no ground shunt) la_oenb[34] = 1 (connect channel) la_data_in[12] = 1 (ground shunt on other channel) la_oenb[33] = 0 (disconnect other channel) reference low = gpio_noesd[9] (pin GPIO 27) when la_data_in[15] = 0 (no ground shunt) la_oenb[36] = 1 (connect channel) la_data_in[14] = 1 (ground shunt on other channel) la_oenb[35] = 0 (disconnect other channel) Vref (trim) = reference voltage = gpio_analog[17] (pin GPIO 35) set externally to 0V nominal (Shared with LDO vref_ext and IDAC vbg) VCM (common mode) = ccomp vinn = gpio_noesd[12] (pin GPIO 30) when la_data_in[8] = 0 (no ground shunt) la_oenb[29] = 1 (connect channel) la_data_in[9] = 1 (ground shunt on other channel) la_oenb[30] = 0 (disconnect other channel) Vin (input for ADC use) = gpio_analog[13] (pin GPIO 31) when la_data_in[7] = 0 (no ground shunt) la_oenb[28] = 1 (connect channel) la_data_in[6] = 1 (ground shunt on other channel) la_oenb[27] = 0 (disconnect other channel) Analog output: CDAC out = ccomp vinp = gpio_noesd[11] (pin GPIO 29) when la_data_in[10] = 0 (no ground shunt) la_oenb[31] = 1 (connect channel) la_data_in[11] = 1 (ground shunt on other channel) la_oenb[32] = 0 (disconnect other channel) (Note that this line is shared with CCOMP VINP for a quick ADC hookup without touching a pad.) Digital inputs: reset = la_oenb[60] hold = la_data_in[90] 12-bit value = la_oenb[54], la_data_in[21], la_oenb[55], la_data_in[22], la_oenb[56], la_data_in[23], la_oenb[57], la_data_in[24], la_oenb[58], la_data_in[25], la_oenb[59], la_data_in[26]
16MHz R-C oscillator (Tim Edwards)
Enable: la_data_in[20] Upstream analog power supply: vdda2/vssa2 Upstream digital power supply: vccd2/vssd2 Power supply monitor: io_analog[6] (pin GPIO 20) Power supply enable: la_data_in[42] Output: io_out[21] (GPIO 32)
Audio sigma-delta ADC output driver (Harald Pretl)
Enable: N/A (As a digital driver, it does not consume power unless driven.) Upstream analog power supply: vccd2/vccd2 (note this is a 1.8V supply) Upstream digital power supply: vccd2/vssd2 Power supply monitor: io_analog[5] (pin GPIO 19) Power supply enable: la_data_in[41] Digital inputs: positive: io_in[26] (GPIO 37) negative: io_in[25] (GPIO 36) Analog outputs: positive: gpio_noesd[16] (pin GPIO 34) when la_data_in[1] = 0 (no ground shunt) la_oenb[22] = 1 (connect channel) la_data_in[0] = 1 (ground shunt on other channel) la_oenb[21] = 0 (disconnect other channel) negative: gpio_noesd[15] (pin GPIO 33) when la_data_in[3] = 0 (no ground shunt) la_oenb[24] = 1 (connect channel) la_data_in[2] = 1 (ground shunt on other channel) la_oenb[23] = 0 (disconnect other channel)
8-bit RDAC (Tim Edwards)
Enable: la_oenb[95] Upstream analog power supply: vdda1/vdda1 Upstream digital power supply: vccd1/vssd1 Power supply monitor: io_analog[0] (pin GPIO 14) Power supply enable: la_data_in[54]
Analog inputs: reference high = gpio_noesd[3] (pin GPIO 10) when la_oenb[103] = 0 (no ground shunt) la_data_in[123] = 1 (connect channel) la_oenb[102] = 1 (ground shunt on other channel) la_data_in[122] = 0 (disconnect other channel) reference low = gpio_noesd[1] (pin GPIO 8) when la_oenb[105] = 0 (no ground shunt) la_data_in[125] = 1 (connect channel) la_oenb[104] = 1 (ground shunt on other channel) la_data_in[124] = 0 (disconnect other channel)
Also:
reference high connects to io_in_3v3[5] (pin GPIO 5)
for quick default setting to 3.3V.
reference low connects to io_in_3v3[6] (pin GPIO 6)
for quick default setting to 0V.
Analog output: RDAC out = gpio_noesd[0] (pin GPIO 7) when la_oenb[106] = 0 (no ground shunt) la_data_in[126] = 1 (connect channel) la_oenb[107] = 1 (ground shunt on other channel) la_data_in[127] = 0 (disconnect other channel) Digital input: la_data_in[115], la_oenb[94], la_data_in[114], la_oenb[93], la_data_in[113], la_oenb[92], la_data_in[112], la_oenb[91]
8-bit rheostat (Tim Edwards)
Enable: N/A Upstream analog power supply: vdda1/vdda1 Upstream digital power supply: vccd1/vssd1 Power supply monitor: io_analog[1] (pin GPIO 15) Power supply enable: la_data_in[53]
Analog inputs: reference high = gpio_noesd[3] (pin GPIO 10) when la_oenb[102] = 0 (no ground shunt) la_data_in[122] = 1 (connect channel) la_oenb[103] = 1 (ground shunt on other channel) la_data_in[123] = 0 (disconnect other channel) reference low = gpio_noesd[1] (pin GPIO 8) when la_oenb[104] = 0 (no ground shunt) la_data_in[124] = 1 (connect channel) la_oenb[105] = 1 (ground shunt on other channel) la_data_in[125] = 0 (disconnect other channel)
Also:
reference high connects to io_in_3v3[3] (pin GPIO 3)
for quick default setting to 3.3V.
reference low connects to io_in_3v3[4] (pin GPIO 4)
for quick default setting to 0V.
Analog output: RDAC out = gpio_noesd[0] (pin GPIO 7) when la_oenb[107] = 0 (no ground shunt) la_data_in[127] = 1 (connect channel) la_oenb[106] = 1 (ground shunt on other channel) la_data_in[126] = 0 (disconnect other channel) Digital input: la_data_in[111], la_oenb[90], la_data_in[110], la_oenb[89], la_data_in[109], la_oenb[88], la_data_in[108], la_oenb[87]
Power-on-reset (POR) (Stephen Wu)
Enable: N/A Bias: gpio_analog[17] (pin GPIO 35) set externally to 1.2V nominal Upstream analog power supply: vdda1/vdda1 Upstream digital power supply: vccd1/vssd1 Power supply monitor: io_analog[2] (pin GPIO 16) Power supply enable: la_data_in[52] Digital outputs: por: io_out[7] (GPIO 7) porb: io_out[8] (GPIO 8) porb_h: gpio_noesd[5] (pin GPIO 12) when la_oenb[98] = 0 (no ground shunt) la_data_in[118] = 1 (connect channel) la_oenb[99] = 1 (ground shunt on other channel) la_data_in[119] = 0 (disconnect other channel)
Instrumentation amplifier (Phil Allen)
Enable: Bias: gpio_noesd[14] (pin GPIO 32) requires current bias source, or set to ? (probably about 0.7V) when la_data_in[4] = 0 (no ground shunt) la_oenb[25] = 1 (connect channel) la_data_in[5] = 0 (disconnect other channel) la_oenb[26] = 1 (ground shunt on other channel) Upstream analog power supply: vdda1/vdda1 Upstream digital power supply: vccd1/vssd1 Power supply monitor: (none) Power supply enable: la_data_in[51] Analog inputs: VINN = gpio_analog[15] (pin GPIO 33) when la_oenb[23] = 1 (connect channel) la_data_in[2] = 0 (no ground shunt) la_oenb[24] = 0 (disconnect other channel) la_data_in[3] = 1 (ground shunt on other channel) VINP = gpio_analog[13] (pin GPIO 31) when la_oenb[27] = 1 (connect channel) la_data_in[6] = 0 (no ground shunt) la_oenb[28] = 0 (disconnect other channel) la_data_in[7] = 1 (ground shunt on other channel) VCM = gpio_analog[17] (pin GPIO 35)
Analog output: gpio_noesd[4] (pin GPIO 11) when la_oenb[100] = 0 (no ground shunt) la_data_in[120] = 1 (connect channel) la_oenb[101] = 1 (ground shunt on other channel) la_data_in[121] = 0 (disconnect other channel)
Digital inputs: V[9:0] = la_data_in[103:94]
Ultra-low-power comparator (Yun Jan Lee)
Enable: la_data_in[107] Upstream analog power supply: vdda1/vssa1 Upstream digital power supply: vccd1/vssd1 Power supply monitor: io_analog[3] (pin GPIO 17) Power supply enable: la_data_in[50] Digital output: io_out[10] (pin GPIO 10) Analog inputs: in positive = gpio_noesd[4] (pin GPIO 11) when la_oenb[101] = 0 (no ground shunt) la_data_in[121] = 1 (connect channel) la_oenb[100] = 1 (ground shunt on other channel) la_data_in[120] = 0 (disconnect other channel) in negative = gpio_noesd[6] (pin GPIO 13) when la_oenb[96] = 0 (no ground shunt) la_data_in[116] = 1 (connect channel) la_oenb[97] = 1 (ground shunt on other channel) la_data_in[117] = 0 (disconnect other channel) Digital clock: la_oenb[86]
Sample-and-hold (Tim Edwards)
Enable: la_data_in[91] Upstream analog power supply: vdda1/vssa1 Upstream digital power supply: vccd1/vssd1 Power supply monitor: N/A Power supply enable: la_data_in[49] Analog input: sample in = gpio_noesd[5] (pin GPIO 12) when la_oenb[99] = 0 (no ground shunt) la_data_in[119] = 1 (connect channel) la_oenb[98] = 1 (ground shunt on other channel) la_data_in[118] = 0 (disconnect other channel) Analog output: sample out = gpio_noesd[6] (pin GPIO 13) when la_oenb[97] = 0 (no ground shunt) la_data_in[117] = 1 (connect channel) la_oenb[96] = 1 (ground shunt on other channel) la_data_in[116] = 0 (disconnect other channel) Digital hold: la_oenb[71]
500kHz R-C oscillator (Tim Edwards)
Enable: la_oenb[70] Upstream analog power supply: vdda1/vssa1 Upstream digital power supply: vccd1/vssd1 Power supply monitor: io_analog[4] (pin GPIO 18) Power supply enable: la_data_in[48] Output: io_out[13] (GPIO 13)
Loopback test
There is a loopback test connecting two switches that allows the switch resistance (specifically, the resistance of two switches in series), and to measure coupling across a switch when the ground isolation is enabled or disabled.
Analog I/O: loopback 1 = gpio_noesd[14] (pin GPIO 32) when la_data_in[5] = 0 (no ground shunt) la_oenb[26] = 1 (connect channel) la_data_in[4] = 1 (ground shunt on other channel) la_oenb[25] = 0 (disconnect other channel) loopback 2 = gpio_noesd[16] (pin GPIO 34) when la_data_in[0] = 0 (no ground shunt) la_oenb[21] = 1 (connect channel) la_data_in[1] = 1 (ground shunt on other channel) la_oenb[22] = 0 (disconnect other channel)