Teo-CD
33c7d0edae
The EEPROM in the cartridges support 'Fast I²C' at 400kHz. Testing it out, it seems to work fine despite the high pull-ups, so update the Arduino code to enjoy the 4x speed-up !
72 lines
1.9 KiB
C++
72 lines
1.9 KiB
C++
#include <Wire.h>
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#include <inttypes.h>
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static const int eeprom_addr = 0b1010000;
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uint8_t pageData[128] = {};
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uint16_t pageAddr = 0;
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void write_addr(uint16_t addr) {
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Wire.write((uint8_t)(addr >> 8));
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Wire.write((uint8_t)addr);
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}
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uint16_t sum_complement(const uint8_t data[128]) {
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uint16_t sum = 0;
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for (int i = 0; i<128; i += 2) {
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sum += (data[i+1] << 8) | data[i];
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}
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return -sum;
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}
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void setup() {
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Serial.begin(115200);
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pinMode(LED_BUILTIN, OUTPUT);
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Wire.begin();
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Wire.setClock(400000);
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}
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void loop() {
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char ret[4] = "";
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// put your main code here, to run repeatedly:
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do {
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if (!Serial.readBytesUntil('\n', ret, 2))
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Serial.read();
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} while (strncmp(ret, "GO", 2) != 0);
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// Reset the EEPROM internal address to 0. It autoincrements after.
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Wire.beginTransmission(eeprom_addr);
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write_addr(0);
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Wire.endTransmission(false);
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digitalWrite(LED_BUILTIN, HIGH);
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/*
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* We don't know the size of the cartridge, and it could be the whole EEPROM.
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* Read and send all the pages (64kiB), it should not impact the final PNG.
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*/
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for (int i = 0; i < 512; i++) {
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memset(pageData, 0, 128);
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// Arduino I2C buffer is 32 bytes, so we need multiple requests per page.
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for (int j = 0; j < 4; j++) {
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Wire.requestFrom(eeprom_addr, 32);
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for (int k = 0; k < 32; k++) {
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pageData[32*j + k] = Wire.read();
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}
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}
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// Try to send the full page until the recipient ACKs
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uint16_t page_checksum = sum_complement(pageData);
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do {
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memset(ret, 0, 4);
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size_t written = 0;
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while (written < 128) {
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written += Serial.write(pageData + written, min(128 - written, 64));
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}
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Serial.write((uint8_t*)&page_checksum, 2);
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while(!Serial.readBytesUntil('\n', ret, 3));
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Serial.read();
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} while(strncmp(ret, "ACK", 3) != 0);
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}
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digitalWrite(LED_BUILTIN, LOW);
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}
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