7i92TH BOB rev 1.0

P1
PIN         Function
1-IO17      STEP0
2-IO18      DIR0
3-IO19      STEP1
4-IO20      DIR1
5-IO21      STEP2
6-IO22      DIR2
7-IO23      STEP3
8-IO24      DIR3
9-IO25      STEP4
11-IO26     DIR4
13-IO27     STEP5
15-IO28     DIR5
17-IO29     SS-RX
19-IO30     SS-TX
21-IO31     GPIO-OUT0
23-IO32     PWM-OUT1
25-IO33     PWM-OUT2

P2
PIN         Function
1-IO0       GPIO-OUT1
2-IO1       GPIO-OUT2
3-IO2       GPIO-OUT3
4-IO3       GPIO-OUT4
5-IO4       GPIO-OUT5
6-IO5       GPIO-IN7
7-IO6       GPIO-IN6
8-IO7       GPIO-IN5
9-IO8       GPIO-IN4
11-IO9      GPIO-IN3
13-IO10     GPIO-IN2
15-IO11     GPIO-IN1
17-IO22     GPIO-IN0
19-IO13     SPI-CS_FRAME
21-IO14     SPI-CS_A0
23-IO15     SPI-MISO
25-IO16     SPI-SCLK

SPI uses decoder chip SN74LVC1G139. Due to decoder having no enable, CS-FRAME is placed on the first address line and only 2 devices are selectable via CS_A0