document hardware wiring

README.md

@@ -12,16 +12,36 @@ Soundboard (computer program), a web application or computer program with button
 ## Wiring
 
 ### SD card
-ESP32 pin     | SD card pin | Notes
+SD card pin   | ESP32 pin     | Notes
---------------|-------------|------------
+--------------|---------------|------------
-GPIO14 (MTMS) | CLK         | 10k pullup
+CS            | GPIO05        |
-GPIO15 (MTDO) | CMD         | 10k pullup
+DI            | GPIO23 (MOSI) |
-GPIO2         | D0          | 10k pullup, pull low to go into download mode
+SCK           | GPIO18 (SCK)  |
-GPIO4         | D1          | 10k pullup; not used in 1-line mode
+DO            | GPIO19 (MISO) |
-GPIO12 (MTDI) | D2          | otherwise 10k pullup (see note below!); not used in 1-line mode
+CD            | GPIO17        | optional
-GPIO13 (MTCK) | D3          | 10k pullup needed at card side, even in 1-line mode
+
-N/C           | CD          |
+### Touch
-N/C           | WP          |
+ESP32 Touch pad | GPIO | Notes
+----------------|------|-------
+T0              | 04   |
+T1              | 00   | also bootloader (not usable on dev board)
+T2              | 02   | also bootloader (not usable on dev board)
+T3              | 15   |
+T4              | 13   |
+T5              | 12   |
+T6              | 14   |
+T7              | 27   |
+T8              | 33   |
+T9              | 32   |
+
+### I2S
+MAX98357A | ESP32 pin
+----------|-----------
+LRC       | 25
+BCLK      | 26
+DIN       | 22
+GAIN      | (VCC)
+SD        | -
 
 
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