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GreenPAK Universal Dev Board 1
This page describes the USB protocol used by the GreenPAK Universal Dev Board 1, as shipped in the GreenPAK 4 Development Kit and probably others as well. Protocol RE is done by @whitequark with board revision v1.3.1 and firmware v2.4.
The protocol is based on USBHID. It uses interrupt URBs, always with a 63 byte payload. All numbers below are in hexadecimal.
Overall URB payload format:
| Offset | Length | Meaning |
|---|---|---|
00 |
01 |
HID report number, always 01
|
01 |
02 |
Packet type |
03 |
01 |
Padding, always zero |
This packet turns the STATUS LED on and off.
| Offset | Length | Meaning |
|---|---|---|
04 |
01 |
STATUS LED enabled |
Read back for WRITE 2104.
This packet configures the I/O buffers, LEDs, and the expansion connector.
Format (everything not specified here was always observed as zeroed):
| Offset | Length | Meaning |
|---|---|---|
04 |
02 |
TP2 output configuration |
06 |
02 |
TP3 output configuration |
08 |
02 |
TP4 output configuration |
0a |
02 |
TP5 output configuration |
0c |
02 |
TP6 output configuration |
0e |
02 |
TP7 output configuration |
10 |
02 |
TP8 output configuration |
12 |
02 |
TP9 output configuration |
14 |
02 |
TP10 output configuration |
16 |
02 |
TP12 output configuration |
18 |
02 |
TP13 output configuration |
1a |
02 |
TP14 output configuration |
1c |
02 |
TP15 output configuration |
1e |
02 |
TP16 output configuration |
20 |
02 |
TP17 output configuration |
22 |
02 |
TP18 output configuration |
24 |
02 |
TP19 output configuration |
26 |
02 |
TP20 output configuration |
2f |
03 |
Expansion connector configuration |
32 |
01 |
TP3..TP6 LED configuration |
33 |
01 |
TP7..TP10 LED configuration |
34 |
01 |
TP12..TP15 LED configuration |
35 |
02 |
TP16..TP20 LED configuration |
37 |
01 |
"POWER" LED status? Always 01
|
TPx output configuration:
| Value | Meaning |
|---|---|
0200 |
N/C |
0c01 |
VDD |
0c00 |
GND |
0e01 |
Pull-up |
0e00 |
Pull-down |
0c03 |
Logic generator, push-pull |
0403 |
Logic generator, open-drain + pull-up |
0603 |
Logic generator, open-drain + pull-down |
0a03 |
Logic generator, open-drain, drives HI |
0803 |
Logic generator, open-drain, drives LO |
0e03 |
Logic generator, open-drain, pull-up/down |
TP3..TP6, TP7..TP10 and TP12..TP15 LED configuration (a bit mask):
| Value | Meaning |
|---|---|
01 |
TP(n+0) LED enabled |
02 |
TP(n+1) LED enabled |
04 |
TP(n+2) LED enabled |
08 |
TP(n+3) LED enabled |
10 |
TP(n+0) LED inverted |
20 |
TP(n+1) LED inverted |
40 |
TP(n+2) LED inverted |
80 |
TP(n+3) LED inverted |
TP16..TP20 LED configuration (a bit mask):
| Value | Meaning |
|---|---|
0100 |
TP(n+0) LED enabled |
0200 |
TP(n+1) LED enabled |
0400 |
TP(n+2) LED enabled |
0800 |
TP(n+3) LED enabled |
1000 |
TP(n+4) LED enabled |
0001 |
TP(n+0) LED inverted |
0002 |
TP(n+1) LED inverted |
0004 |
TP(n+2) LED inverted |
0008 |
TP(n+3) LED inverted |
0010 |
TP(n+4) LED inverted |
Expansion connector configuration (a bit mask):
| Value | Meaning |
|---|---|
000100 |
VDD |
000004 |
TP2 |
000001 |
TP3 |
000010 |
TP4 |
000040 |
TP5 |
010000 |
TP6 |
040000 |
TP7 |
100000 |
TP8 |
400000 |
TP9 |
800000 |
TP10 |
200000 |
TP12 |
000008 |
TP13 |
000002 |
TP14 |
008000 |
TP15 |
000020 |
TP16 |
020000 |
TP17 |
002000 |
TP18 |
000800 |
TP19 |
080000 |
TP20 |