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Improvements to SD media detection, esp. when using nor flash on 5.2

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This commit is contained in:
Michael McMaster 2021-03-11 20:33:55 +10:00
parent f71e9a3355
commit 14ba62e8e3
1 changed files with 25 additions and 17 deletions
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42
software/SCSI2SD/src/sd.c
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@ -977,6 +977,24 @@ void sdPoll()
} }
} }
static int
sdIsCardPresent()
{
// The CS line is pulled high by the SD card.
// De-assert the line, and check if it's high.
// This isn't foolproof as it'll be left floating without
// an SD card. We can't use the built-in pull-down resistor as it will
// overpower the SD pullup resistor.
SD_CS_Write(0);
SD_CS_SetDriveMode(SD_CS_DM_DIG_HIZ);
// Delay extended to work with 60cm cables running cards at 2.85V
CyDelayCycles(128);
int cs = SD_CS_Read();
SD_CS_SetDriveMode(SD_CS_DM_STRONG);
return cs;
}
void sdCheckPresent() void sdCheckPresent()
{ {
static int firstCheck = 1; static int firstCheck = 1;
@ -985,31 +1003,21 @@ void sdCheckPresent()
(sdIOState == SD_IDLE) && (sdIOState == SD_IDLE) &&
(sdCmdState == CMD_STATE_IDLE)) (sdCmdState == CMD_STATE_IDLE))
{ {
// The CS line is pulled high by the SD card. int cs = sdIsCardPresent();
// De-assert the line, and check if it's high.
// This isn't foolproof as it'll be left floating without
// an SD card. We can't use the built-in pull-down resistor as it will
// overpower the SD pullup resistor.
SD_CS_Write(0);
SD_CS_SetDriveMode(SD_CS_DM_DIG_HIZ);
// Delay reduced for v5.2 board, no support for extension cables.
CyDelayCycles(32);
uint8_t cs = SD_CS_Read();
SD_CS_SetDriveMode(SD_CS_DM_STRONG);
if (cs && !(sdCard.dev.mediaState & MEDIA_PRESENT)) if (cs && !(sdCard.dev.mediaState & MEDIA_PRESENT))
{ {
static int firstInit = 1; static int firstInit = 1;
// Debounce, except on startup if the card is present at // Debounce. Quicker if the card is present at
// power on // power on
if (!firstCheck) for (int i = 0; cs && (i < firstCheck ? 2 : 50); ++i)
{ {
CyDelay(250); cs = sdIsCardPresent();
CyDelay(5);
} }
if (sdInit()) if (cs && sdInit())
{ {
sdCard.dev.mediaState |= MEDIA_PRESENT | MEDIA_INITIALISED; sdCard.dev.mediaState |= MEDIA_PRESENT | MEDIA_INITIALISED;
@ -1093,8 +1101,8 @@ static int sd_pollMediaChange(S2S_Device* dev)
SdCard* sdCardDevice = (SdCard*)dev; SdCard* sdCardDevice = (SdCard*)dev;
if (elapsedTime_ms(sdCardDevice->lastPollMediaTime) > 200) if (elapsedTime_ms(sdCardDevice->lastPollMediaTime) > 200)
{ {
sdCardDevice->lastPollMediaTime = getTime_ms();
sdCheckPresent(); sdCheckPresent();
sdCardDevice->lastPollMediaTime = getTime_ms();
return 0; return 0;
} }
else else