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Refactor to reduce RTC code size.

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This commit is contained in:
Andrew Makousky 2020-09-17 00:22:26 -05:00
parent 4e6537e57a
commit c4d34dae71
1 changed files with 64 additions and 85 deletions
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149
firmware/rtc/MacRTC.c
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@ -38,6 +38,7 @@
// Simplified Arduino.h definitions.
typedef enum { false, true } bool; // Compatibility with C++.
typedef bool boolean;
typedef uint8_t bool8_t;
typedef uint8_t byte;
#define bitRead(value, bit) (((value) >> (bit)) & 0x01)
@ -211,13 +212,10 @@ enum SerialStateType { SERIAL_DISABLED, RECEIVING_COMMAND,
SENDING_DATA, RECEIVING_DATA,
RECEIVING_XCMD_ADDR, RECEIVING_XCMD_DATA };
enum PramAddrResult { INVALID_CMD, SECONDS_CMD,
WRTEST_CMD, WRPROT_CMD, SUCCESS_ADDR };
volatile boolean lastRTCEnable = 0;
volatile boolean lastSerClock = 0;
volatile boolean serClockRising = false;
volatile boolean serClockFalling = false;
volatile bool8_t lastRTCEnable = 0;
volatile bool8_t lastSerClock = 0;
volatile bool8_t serClockRising = false;
volatile bool8_t serClockFalling = false;
volatile byte serialState = SERIAL_DISABLED;
volatile byte serialBitNum = 0;
@ -360,7 +358,7 @@ void oflowInterrupt(void)
*/
void handleRTCEnableInterrupt(void)
{
boolean curRTCEnable = PINB&(1<<RTC_ENABLE_PIN);
bool8_t curRTCEnable = PINB&(1<<RTC_ENABLE_PIN);
if (lastRTCEnable && !curRTCEnable){ // Simulates a falling interrupt
serialState = RECEIVING_COMMAND;
}
@ -376,7 +374,7 @@ void handleRTCEnableInterrupt(void)
*/
void handleSerClockInterrupt(void)
{
boolean curSerClock = PINB&(1<<SERIAL_CLOCK_PIN);
bool8_t curSerClock = PINB&(1<<SERIAL_CLOCK_PIN);
if (!lastSerClock && curSerClock) {
serClockRising = true;
serClockFalling = false;
@ -389,44 +387,66 @@ void handleSerClockInterrupt(void)
lastSerClock = curSerClock;
}
/*
* For 20-byte PRAM equivalent commands, compute the actual PRAM
* address by modifying the `address` variable in-place. A status
* code is returned for commands that need special processing:
*
* INVALID_CMD: Invalid command byte.
* SECONDS_CMD: Special command: read seconds.
* WRTEST_CMD: Special command: test write register.
* WRPROT_CMD: Special command: write-protect register.
* SUCCESS_ADDR: Successful address computation.
*/
uint8_t decodePramCmd(boolean writeRequest)
/* For 20-byte PRAM equivalent commands, execute the PRAM command.
Return `false` on invalid commands. */
bool8_t execTradPramCmd(bool8_t writeRequest)
{
// Discard the first bit and the last two bits, it's not pertinent
// to address interpretation.
address = (address&~(1<<7))>>2;
if (address < 8) {
// Discard the first bit and the last two address bits, it's not
// pertinent to address interpretation. Also, use a local,
// non-volatile variable to save code size.
byte lAddress = (address&~(1<<7))>>2;
if (writeRequest && writeProtect &&
lAddress != 13) // 13 == update write-protect register
return true; // nothing to be done
if (lAddress < 8) {
// Little endian clock data byte
return SECONDS_CMD;
} else if (address < 12) {
// Group 2 register
address = (address&0x03) + group2Base;
} else if (address < 16) {
cli(); // Ensure that reads/writes are atomic.
if (writeRequest) {
if (address == 12) // test write
return WRTEST_CMD;
if (address == 13) // write-protect
return WRPROT_CMD;
// Addresses 14 and 15 are used for the encoding of the first
// byte of an extended command.
lAddress = (lAddress&0x03)<<3;
seconds &= ~((unsigned long)0xff<<lAddress);
seconds |= (unsigned long)serialData<<lAddress;
} else {
lAddress = (lAddress&0x03)<<3;
serialData = (seconds>>lAddress)&0xff;
// Fall through to send data to host.
}
return INVALID_CMD;
sei();
} else if (lAddress < 12) {
// Group 2 register
lAddress = (lAddress&0x03) + group2Base;
if (writeRequest)
pram[lAddress] = serialData;
else {
serialData = pram[lAddress];
// Fall through to send data to host.
}
} else if (lAddress < 16) {
if (writeRequest) {
if (lAddress == 12) // test write, do nothing
;
else if (lAddress == 13) {
// Update the write-protect register.
writeProtect = ((serialData & 0x80)) ? 1 : 0;
}
else {
// Addresses 14 and 15 are used for the encoding of the first
// byte of an extended command. Therefore, interpretation as
// a traditional PRAM command is invalid.
}
} else
return false; // invalid command
} else {
// Group 1 register
address = (address&0x0f) + group1Base;
lAddress = (lAddress&0x0f) + group1Base;
if (writeRequest)
pram[lAddress] = serialData;
else {
serialData = pram[lAddress];
// Fall through to send data to host.
}
}
return SUCCESS_ADDR;
return true;
}
void loop(void)
@ -447,7 +467,7 @@ void loop(void)
serialBitNum >= 9) {
clearState();
} else */ if (serClockFalling) {
boolean writeRequest;
bool8_t writeRequest;
switch(serialState) {
case RECEIVING_COMMAND:
shiftReadPB(address, 7 - serialBitNum, SERIAL_DATA_PIN);
@ -475,25 +495,8 @@ void loop(void)
serialBitNum = 0;
break;
} else {
boolean finished = false;
// Decode the command/address.
switch (decodePramCmd(false)) {
case SECONDS_CMD:
// Read little endian clock data byte.
cli(); // Ensure that reads are atomic.
address = (address&0x03)<<3;
serialData = (seconds>>address)&0xff;
sei();
break;
case SUCCESS_ADDR:
serialData = pram[address];
break;
case INVALID_CMD:
default:
finished = true;
break;
}
if (finished) {
// Execute the command.
if (!execTradPramCmd(false)) {
clearState();
break;
}
@ -512,32 +515,8 @@ void loop(void)
if (serialBitNum <= 7)
break;
// Decode the command/address.
switch (decodePramCmd(true)) {
case SECONDS_CMD:
if (!writeProtect) {
// Write little endian clock data byte.
cli(); // Ensure that writes are atomic.
address = (address&0x03)<<3;
seconds &= ~((unsigned long)0xff<<address);
seconds |= (unsigned long)serialData<<address;
sei();
}
break;
case WRPROT_CMD:
// Update the write-protect register.
writeProtect = ((serialData & 0x80)) ? 1 : 0;
break;
case SUCCESS_ADDR:
if (!writeProtect)
pram[address] = serialData;
break;
case WRTEST_CMD: // test write, do nothing
case INVALID_CMD:
default:
break;
}
// Execute the command.
execTradPramCmd(true);
// Finished with the write command.
clearState();
break;