Git-Mirrors/OpenModem
1
0
Fork 0
mirror of https://github.com/markqvist/OpenModem.git synced 2024-10-01 03:15:46 -04:00
Code Issues Actions Packages Projects Releases Wiki Activity

Before Hamming code

Browse Source
This commit is contained in:
Mark Qvist 2014-04-13 15:42:48 +02:00
parent dbe32bd02e
commit 3644a35b79
3 changed files with 18 additions and 19 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

34
Modem/afsk.c
View File

@ -93,7 +93,7 @@ INLINE uint8_t sinSample(uint16_t i) {
#define PHASE_BITS 8 // How much to increment phase counter each sample
#define PHASE_INC 1 // Nudge by an eigth of a sample each adjustment
#define PHASE_MAX (SAMPLESPERBIT * PHASE_BITS) // Resolution of our phase counter = 64
#define PHASE_THRESHOLD (PHASE_MAX / 4) // Target transition point of our phase window
#define PHASE_THRESHOLD (PHASE_MAX / 2) // Target transition point of our phase window
// Modulation constants
#define MARK_FREQ 1200 // The tone frequency signifying a binary one
@ -373,24 +373,24 @@ void afsk_adc_isr(Afsk *afsk, int8_t currentSample) {
// more 1's, we will assume that the transmitter
// sent us a one, otherwise we assume a zero
uint8_t bits = afsk->sampledBits & 0x0f;
uint8_t c = 0;
c += bits & BV(1);
c += bits & BV(2);
c += bits & BV(3);
c += bits & BV(4);
c += bits & BV(5);
if (c >= 3) afsk->actualBits |= 1;
// uint8_t bits = afsk->sampledBits & 0x0f;
// uint8_t c = 0;
// c += bits & BV(1);
// c += bits & BV(2);
// c += bits & BV(3);
// c += bits & BV(4);
// c += bits & BV(5);
// if (c >= 3) afsk->actualBits |= 1;
//// Alternative using only three bits //////////
// uint8_t bits = afsk->sampledBits & 0x07;
// if (bits == 0x07 || // 111
// bits == 0x06 || // 110
// bits == 0x05 || // 101
// bits == 0x03 // 011
// ) {
// afsk->actualBits |= 1;
// }
uint8_t bits = afsk->sampledBits & 0x07;
if (bits == 0x07 || // 111
bits == 0x06 || // 110
bits == 0x05 || // 101
bits == 0x03 // 011
) {
afsk->actualBits |= 1;
}
/////////////////////////////////////////////////
// Now we can pass the actual bit to the HDLC parser.

1
Modem/hardware.c
View File

@ -67,7 +67,6 @@ void hw_afsk_adcInit(int ch, Afsk *_modem)
// temperature variations, but if you have a board with a
// crystal that is way off frequency, this can help alot.
ICR1 = (((CPU_FREQ+FREQUENCY_CORRECTION)) / 9600) - 1;
kprintf("ICR1=%d",ICR1);
// Set reference to AVCC (5V), select pin
// Set the ADMUX register. The first part (BV(REFS0)) sets

2
buildrev.h
View File

@ -1,2 +1,2 @@
#define VERS_BUILD 549
#define VERS_BUILD 577
#define VERS_HOST "vixen"