Disable all peripheral functions globally. Enable used functions when needed.

diff --git a/avr/i2c.c b/avr/i2c.c
index dbb5da15e19ec122e69bba24894d1f3e2710cfbd..e0e5a1990b4086248752ecd9b0ccd6a9652aa4d9 100644 (file)
--- a/avr/i2c.c
+++ b/avr/i2c.c
@@ -1,6 +1,6 @@
 
-/* 
- * I2C (TWI) master interface. 
+/*
+ * I2C (TWI) master interface.
  */
 
 #include "common.h"
@@ -48,33 +48,33 @@
  * TWSTO: TWI STOP Condition Bit
  * TWEN:  TWI Enable Bit
  * TWIE:  TWI Interrupt Enable
- * 
+ *
  *     (1<<TWEN)|(1<<TWIE)|(1<<TWINT)
  *     (1<<TWEN)|(1<<TWIE)|(1<<TWINT)|           (1<<TWEA)
  *     (1<<TWEN)|(1<<TWIE)|(1<<TWINT)
- * 
+ *
  * default:
  *     (1<<TWEN)|          (1<<TWINT)|           (1<<TWSTO)
- * 
+ *
  * Init:
  *     (1<<TWEN)
- * 
+ *
  * start read/write:
  *     (1<<TWEN)|(1<<TWIE)|(1<<TWINT)|(1<<TWSTA)
  *     (1<<TWEN)|(1<<TWIE)|(1<<TWINT)|(1<<TWSTA)
  *     (1<<TWEN)|(1<<TWIE)|(1<<TWINT)|(1<<TWSTA)
  *     (1<<TWEN)|(1<<TWIE)|(1<<TWINT)|(1<<TWSTA)
- * 
+ *
  * wait ready:
  *      (1<<TWIE)|(1<<TWSTO)
  *
  *
  *
- *i2c_result   
+ *i2c_result
  *
  *     0b10000000      Busy (Transmission in progress)
  *     0b01000000      Timeout
- *     0b00001000      Start transmitted 
+ *     0b00001000      Start transmitted
  *     0b00000100      Slave acknowledged address
  *     0b00000010      Data byte(s) transmitted/received
  *     0b00000001      Transmission completed
@@ -86,8 +86,8 @@
 #define TWI_C_DISABLE          0x00
 #define TWI_C_ENABLE           (1<<TWEN)
 
- 
- 
+
+
  typedef struct i2c_msg_s {
        uint8_t stat;
  #define XMIT_DONE     (1<<0)
@@ -114,7 +114,7 @@ ISR(TWI_vect)
        tmp_stat = xmit.stat;
 
        uint8_t twsr = TWSR;
-               
+
        switch (twsr & 0xf8) {
 
        case TWI_START:
@@ -223,7 +223,7 @@ void i2c_init(uint32_t speed)
 {
        twps = 0;
        uint32_t tmp_twbr = F_CPU /2 / speed - 8;
-       
+
        while (tmp_twbr > 255) {
                tmp_twbr >>= 4;
                twps += 1;
@@ -231,6 +231,8 @@ void i2c_init(uint32_t speed)
        debug_cond((twps > 3), "*** TWCLK too low: %lu Hz\n", speed);
 
        twbr = (uint8_t) tmp_twbr;
+
+       PRR0 &= ~_BV(PRTWI);
        _init();
 }
 
@@ -239,7 +241,7 @@ int_fast8_t i2c_waitready(void)
 {
        uint32_t timer = get_timer(0);
        uint8_t timeout = 0;
-       
+
        do {
                if (get_timer(timer) >= 30) {
                        timeout = TIMEOUT;
@@ -252,7 +254,7 @@ int_fast8_t i2c_waitready(void)
 #if DEBUG_I2C
        dump_ram((uint8_t *) &xmit, 4, "=== i2c_wait ready: (done)");
        _delay_ms(30);
-#endif 
+#endif
        return xmit.stat;
 }
 
@@ -275,11 +277,11 @@ int i2c_send(uint8_t chip, uint16_t addr, uint8_t alen, uint8_t *buffer, int8_t
        for (n = len + i; i < n; i++)
                xmit.buf[i] = *buffer++;
        xmit.len = i;
-       
+
 #if DEBUG_I2C
        dump_ram((uint8_t *) &xmit, 0x20, "=== i2c_send");
        _delay_ms(30);
-#endif 
+#endif
        /* Enable TWI, TWI int and initiate start condition */
        TWCR = (1<<TWEN)|(1<<TWIE)|(1<<TWINT)|(1<<TWSTA);
 
@@ -339,13 +341,13 @@ int i2c_write(uint8_t chip, unsigned int addr, uint_fast8_t alen,
                                uint8_t *buffer, uint_fast8_t len)
 {
        int rc;
-       
+
        if ((alen > 2) || (1 + alen + len > CONFIG_SYS_I2C_BUFSIZE)) {
                debug("** i2c_write: buffer overflow, alen: %u, len: %u\n",
                        alen, len);
                return -1;
        }
-       
+
        i2c_send(chip, addr, alen, buffer, len);
        rc = i2c_waitready();
 
@@ -362,10 +364,10 @@ int i2c_read(uint8_t chip, unsigned int addr, uint_fast8_t alen,
                        alen, len);
                return -1;
        }
-       
+
        if (alen != 0) {
                i2c_send(chip, addr, alen, NULL, 0);
-       }       
+       }
        rc = i2c_recv(chip, buffer, len);
 
        return !((rc & (XMIT_DONE|DATA_ACK)) == (XMIT_DONE|DATA_ACK));

diff --git a/avr/main.c b/avr/main.c
index 65622ccfe5316d11d8cb5908809218bb397508c6..9d7c89feaa9c2412147bed0def0511ecb4ac881c 100644 (file)
--- a/avr/main.c
+++ b/avr/main.c
@@ -77,11 +77,15 @@ void setup_avr(void)
        MCUCR = _BV(JTD);
        MCUCR = _BV(JTD);
 
-       /* disable unused peripherals */
-       PRR0 = _BV(PRTIM0) | _BV(PRADC);
+       /* Disable peripherals. Enable individually in respective init function. */
+       PRR0 = _BV(PRTWI) |
+               _BV(PRTIM2) | _BV(PRTIM0) | _BV(PRTIM1) |
+               _BV(PRSPI) | _BV(PRUSART0) | _BV(PRADC);
+
        PRR1 = _BV(PRTIM5) | _BV(PRTIM4) | _BV(PRTIM3) |
                _BV(PRUSART3) | _BV(PRUSART2) | _BV(PRUSART1);
 
+
        /* disable analog comparator */
        ACSR = _BV(ACD);
        /* Ports */
@@ -91,7 +95,7 @@ void setup_avr(void)
        CLKPR = 0;
 
        /* Timer */
-
+       PRR0 &= ~_BV(PRTIM2);
        OCR2A = F_CPU / 256 / 1000 - 1; /* Timer2: 1000Hz interval (OC2A) */
        TCCR2A = (0b10 << WGM20);       /* CTC Mode */
        TCCR2B = (0b110 << CS20);       /* Prescaler 256 */

diff --git a/avr/z80-if.c b/avr/z80-if.c
index c0f128e1a4870005d543becf1adf5a47b1c8776b..dd0dd96414e2a91a1494987c8b6e703f2f57a954 100644 (file)
--- a/avr/z80-if.c
+++ b/avr/z80-if.c
@@ -144,6 +144,7 @@ struct bits {
 #define MASK(n)        ((1<<(n))-1)
 #define SMASK(w,s) (MASK(w) << (s))
 
+#define LOWSPEED       50000
 
 
 typedef union {
@@ -157,6 +158,13 @@ static zstate_t zstate;
 
 /*--------------------------------------------------------------------------*/
 
+static
+uint8_t is_lowspeed()
+{
+       return (TCCR1B & 7) < 2 &&
+               OCR1A > (F_CPU / 2 / LOWSPEED);
+}
+
 static
 void z80_setup_clock(void)
 {
@@ -206,12 +214,10 @@ int z80_clock_set(unsigned long freq)
        TCCR1A = (0b01 << COM1C0) | (0b00 << WGM10);
        TCCR1B = (0b01 << WGM12)  | ((prescale+1) << CS10);
 
-       if (ocrval == 0) {
-//             TCCR1C |= _BV(FOC1C);
+       if (ocrval == 0)
                ATOMIC_BLOCK(ATOMIC_RESTORESTATE) {
                        TCNT1 = 0xFFFF;
                }
-       }
 
        PINB |= _BV(6);         /* Debug */
 
@@ -229,7 +235,6 @@ uint32_t z80_clock_get(void)
                else
                        count *= 8;
                pre--;
-
        }
 
        return F_CPU/count;