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Merge pull request #5792 from etracer65/max7456_init

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Avoid 0xFF character when writing to MAX7456 in auto-increment mode
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Michael Keller 2018-05-03 13:11:21 +12:00 • committed by GitHub
commit d85f263028
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1 changed files with 26 additions and 3 deletions
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29
src/main/drivers/max7456.c
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@ -653,18 +653,41 @@ void max7456DrawScreen(void)
static void max7456DrawScreenSlow(void) static void max7456DrawScreenSlow(void)
{ {
bool escapeCharFound;
ENABLE_MAX7456; ENABLE_MAX7456;
// Enable auto-increment mode and update every character in the screenBuffer.
// The "escape" character 0xFF must be skipped as it causes the MAX7456 to exit auto-increment mode.
max7456Send(MAX7456ADD_DMAH, 0); max7456Send(MAX7456ADD_DMAH, 0);
max7456Send(MAX7456ADD_DMAL, 0); max7456Send(MAX7456ADD_DMAL, 0);
max7456Send(MAX7456ADD_DMM, displayMemoryModeReg | 1); max7456Send(MAX7456ADD_DMM, displayMemoryModeReg | 1);
for (int xx = 0; xx < maxScreenSize; ++xx) { for (int xx = 0; xx < maxScreenSize; xx++) {
max7456Send(MAX7456ADD_DMDI, screenBuffer[xx]); if (screenBuffer[xx] == END_STRING) {
escapeCharFound = true;
max7456Send(MAX7456ADD_DMDI, ' '); // replace the 0xFF character with a blank in the first pass to avoid terminating auto-increment
} else {
max7456Send(MAX7456ADD_DMDI, screenBuffer[xx]);
}
shadowBuffer[xx] = screenBuffer[xx]; shadowBuffer[xx] = screenBuffer[xx];
} }
max7456Send(MAX7456ADD_DMDI, 0xFF); max7456Send(MAX7456ADD_DMDI, END_STRING);
max7456Send(MAX7456ADD_DMM, displayMemoryModeReg); max7456Send(MAX7456ADD_DMM, displayMemoryModeReg);
// If we found any of the "escape" character 0xFF, then make a second pass
// to update them with direct addressing
if (escapeCharFound) {
for (int xx = 0; xx < maxScreenSize; xx++) {
if (screenBuffer[xx] == END_STRING) {
max7456Send(MAX7456ADD_DMAH, xx >> 8);
max7456Send(MAX7456ADD_DMAL, xx & 0xFF);
max7456Send(MAX7456ADD_DMDI, END_STRING);
}
}
}
DISABLE_MAX7456; DISABLE_MAX7456;
} }