diff options
| -rw-r--r-- | openpcd/firmware/src/os/tc_cdiv.c | 101 | ||||
| -rw-r--r-- | openpcd/firmware/src/os/tc_cdiv.h | 23 |
2 files changed, 124 insertions, 0 deletions
diff --git a/openpcd/firmware/src/os/tc_cdiv.c b/openpcd/firmware/src/os/tc_cdiv.c new file mode 100644 index 0000000..b15f7b1 --- /dev/null +++ b/openpcd/firmware/src/os/tc_cdiv.c @@ -0,0 +1,101 @@ +/* OpenPC TC (Timer / Clock) support code + * (C) 2006 by Harald Welte <hwelte@hmw-consulting.de> + * + * This idea of this code is to feed the 13.56MHz carrier clock of RC632 + * into TCLK1, which is routed to XC1. Then configure TC0 to divide this + * clock by a configurable divider. + * + * PICC Simulator Side: + * In order to support responding to synchronous frames (REQA/WUPA/ANTICOL), + * we need a second Timer/Counter (TC1). This unit is reset by an external + * event (rising edge of modulation pause PCD->PICC) connected to TIOB2, and + * counts up to a configurable number of carrier clock cycles (RA). Once the + * RA value is reached, TIOA2 will see a rising edge. This rising edge will + * be interconnected to TF (Tx Frame) of the SSC to start transmitting our + * synchronous response. + * + */ + +#include <lib_AT91SAM7.h> +#include <AT91SAM7.h> +#include <os/dbgu.h> + +#include "../openpcd.h" +#include <os/tc_cdiv.h> + +static AT91PS_TCB tcb = AT91C_BASE_TCB; + +/* set carrier divider to a specific */ +void tc_cdiv_set_divider(u_int16_t div) +{ + tcb->TCB_TC0.TC_RC = div; + + /* set to 50% duty cycle */ + tcb->TCB_TC0.TC_RA = 1; + tcb->TCB_TC0.TC_RB = 1 + (div >> 1); +} + +void tc_cdiv_phase_add(int16_t inc) +{ + tcb->TCB_TC0.TC_RA = (tcb->TCB_TC0.TC_RA + inc) % tcb->TCB_TC0.TC_RC; + tcb->TCB_TC0.TC_RB = (tcb->TCB_TC0.TC_RB + inc) % tcb->TCB_TC0.TC_RC; + + /* FIXME: can this be done more elegantly? */ + if (tcb->TCB_TC0.TC_RA == 0) { + tcb->TCB_TC0.TC_RA += 1; + tcb->TCB_TC0.TC_RB += 1; + } +} + +void tc_cdiv_init(void) +{ + /* Cfg PA28(TCLK1), PA0(TIOA0), PA1(TIOB0), PA20(TCLK2) as Periph B */ + AT91F_PIO_CfgPeriph(AT91C_BASE_PIOA, 0, + OPENPCD_PIO_CARRIER_IN | + OPENPCD_PIO_CARRIER_DIV_OUT | + OPENPCD_PIO_CDIV_HELP_OUT | + OPENPCD_PIO_CDIV_HELP_IN); + + AT91F_PMC_EnablePeriphClock(AT91C_BASE_PMC, + ((unsigned int) 1 << AT91C_ID_TC0)); + + /* Enable Clock for TC0 */ + tcb->TCB_TC0.TC_CCR = AT91C_TC_CLKEN; + + /* Connect TCLK1 to XC1, TCLK2 to XC2 */ + tcb->TCB_BMR &= ~(AT91C_TCB_TC1XC1S | AT91C_TCB_TC2XC2S); + tcb->TCB_BMR |= (AT91C_TCB_TC1XC1S_TCLK1 | AT91C_TCB_TC2XC2S_TCLK2); + + /* Clock XC1, Wave mode, Reset on RC comp + * TIOA0 on RA comp = set, * TIOA0 on RC comp = clear, + * TIOB0 on EEVT = set, TIOB0 on RB comp = clear, + * EEVT = XC2 (TIOA0) */ + tcb->TCB_TC0.TC_CMR = AT91C_TC_CLKS_XC1 | AT91C_TC_WAVE | + AT91C_TC_WAVESEL_UP_AUTO | + AT91C_TC_ACPA_SET | AT91C_TC_ACPC_CLEAR | + AT91C_TC_BEEVT_SET | AT91C_TC_BCPB_CLEAR | + AT91C_TC_EEVT_XC2 | AT91C_TC_ETRGEDG_RISING; + + tc_cdiv_set_divider(128); + + /* Reset to start timers */ + tcb->TCB_BCR = 1; +} + +void tc_cdiv_print(void) +{ + DEBUGP("TCB_BMR=0x%08x ", tcb->TCB_BMR); + DEBUGP("TC0_CV=0x%08x ", tcb->TCB_TC0.TC_CV); + DEBUGP("TC0_CMR=0x%08x ", tcb->TCB_TC0.TC_CMR); + DEBUGPCR("TC0_SR=0x%08x", tcb->TCB_TC0.TC_SR); + + DEBUGPCR("TC0_RA=0x%04x, TC0_RB=0x%04x, TC0_RC=0x%04x", + tcb->TCB_TC0.TC_RA, tcb->TCB_TC0.TC_RB, tcb->TCB_TC0.TC_RC); +} + +void tc_cdiv_fini(void) +{ + tcb->TCB_TC0.TC_CCR = AT91C_TC_CLKDIS; + AT91F_PMC_DisablePeriphClock(AT91C_BASE_PMC, + ((unsigned int) 1 << AT91C_ID_TC0)); +} diff --git a/openpcd/firmware/src/os/tc_cdiv.h b/openpcd/firmware/src/os/tc_cdiv.h new file mode 100644 index 0000000..8b4031d --- /dev/null +++ b/openpcd/firmware/src/os/tc_cdiv.h @@ -0,0 +1,23 @@ +#ifndef _TC_CDIV_H +#define _TC_CDIV_H + +#include <sys/types.h> + +extern void tc_cdiv_phase_add(int16_t inc); +extern void tc_cdiv_set_divider(u_int16_t div); + +static inline void tc_cdiv_phase_inc(void) +{ + tc_cdiv_phase_add(1); +} + +static inline void tc_cdiv_phase_dec(void) +{ + tc_cdiv_phase_add(-1); +} + +extern void tc_cdiv_print(void); +extern void tc_cdiv_init(void); +extern void tc_cdiv_fini(void); + +#endif |