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/*
* Copyright © 2017 Keith Packard <keithp@keithp.com>
*
* This program is free software; you can redistribute it and/or modify
* it under the terms of the GNU General Public License as published by
* the Free Software Foundation, either version 2 of the License, or
* (at your option) any later version.
*
* This program is distributed in the hope that it will be useful, but
* WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
* General Public License for more details.
*/
#include <ao.h>
#include <ao_flip_bits.h>
#include <ao_1802.h>
#include <ao_exti.h>
/* Signals muxed between 1802 and STM */
uint8_t MRD, TPB, TPA, MWR;
/* Decoded address driven by TPA/TPB signals */
uint16_t ADDRESS;
/* Decoded data, driven by TPB signal */
uint8_t DATA;
/* Mux control */
#define MUX_1802 0
#define MUX_STM 1
uint8_t MUX_CONTROL;
/* Signals driven by 1802 only */
uint8_t WAIT, CLEAR, Q, SC, N;
uint8_t DMA_IN, DMA_OUT, INTERRUPT;
uint8_t EF;
static uint8_t ma_stm;
uint8_t
MA(void) {
if (MUX_CONTROL == MUX_1802)
return (ao_gpio_get_all(MA_PORT) >> MA_SHIFT) & 0xff;
else
return ma_stm;
}
static void
MA_set(uint8_t ma) {
ao_gpio_set_mask(MA_PORT, ((uint16_t) ma) << MA_SHIFT, 0xff << MA_SHIFT);
ma_stm = ma;
}
static uint8_t data_stm;
static uint8_t
DATA_get(void) {
if (MUX_CONTROL == MUX_1802)
return ao_flip_bits[(ao_gpio_get_all(DATA_PORT) >> DATA_SHIFT) & 0xff];
else
return data_stm;
}
static void
DATA_set(uint8_t data) {
ao_gpio_set_mask(DATA_PORT, ((uint16_t) ao_flip_bits[data]) << DATA_SHIFT, 0xff << DATA_SHIFT);
data_stm = data;
}
static uint8_t
N_get(void) {
return (ao_gpio_get_all(N_PORT) >> N_SHIFT) & 0x7;
}
static uint8_t
EF_get(void) {
return (ao_gpio_get_all(EF_PORT) >> EF_SHIFT) & 0xf;
}
static uint8_t
Q_get(void) {
return ao_gpio_get(Q_PORT, Q_BIT, Q_PIN);
}
static uint8_t
SC_get(void) {
static const uint8_t flip_sc[4] = { 0, 2, 1, 3 };
return flip_sc[(ao_gpio_get_all(SC_PORT) >> SC_SHIFT) & 3];
}
void
mrd(uint8_t value) { MRD = value; }
void
mwr(uint8_t value) { MWR = value; }
void
tpb(uint8_t value) {
TPB = value;
/* Latch low address and data on rising edge of TPB */
if (TPB) {
ADDRESS = (ADDRESS & 0xff00) | MA();
DATA = DATA_get();
N = N_get();
ao_wakeup(&ADDRESS);
}
}
void
tpa(uint8_t value) {
TPA = value;
/* Latch high address on rising edge of TPA */
if (TPA) {
ADDRESS = (ADDRESS & 0x00ff) | ((uint16_t) MA() << 8);
SC = SC_get();
if (SC == SC_EXECUTE)
EF = EF_get();
ao_wakeup(&ADDRESS);
}
}
#define ao_1802_in(port, bit, callback) do { \
ao_enable_input(port, bit, 0); \
ao_exti_enable(port, bit); \
ao_exti_set_callback(port, bit, callback); \
(*callback)(); \
} while (0)
static void mrd_isr(void) { mrd(ao_gpio_get(MRD_PORT, MRD_BIT, MRD_PIN)); }
static void mwr_isr(void) { mwr(ao_gpio_get(MWR_PORT, MWR_BIT, MWR_PIN)); }
static void tpb_isr(void) { tpb(ao_gpio_get(TPB_PORT, TPB_BIT, TPB_PIN)); }
static void tpa_isr(void) { tpa(ao_gpio_get(TPA_PORT, TPA_BIT, TPA_PIN)); }
static void q_isr(void) { Q = Q_get(); }
static void
ao_set_1802(void)
{
ao_gpio_set(MUX_PORT, MUX_BIT, MUX_PIN, 0);
ao_1802_in(MRD_PORT, MRD_BIT, mrd_isr);
ao_1802_in(MWR_PORT, MWR_BIT, mwr_isr);
ao_1802_in(TPB_PORT, TPB_BIT, tpb_isr);
ao_1802_in(TPA_PORT, TPA_BIT, tpa_isr);
MUX_CONTROL = MUX_1802;
}
static void
ao_set_arm(void)
{
ao_enable_output(MRD_PORT, MRD_BIT, MRD_PIN, 1);
ao_enable_output(MWR_PORT, MWR_BIT, MWR_PIN, 1);
ao_enable_output(TPB_PORT, TPB_BIT, TPB_PIN, 0);
ao_enable_output(TPA_PORT, TPA_BIT, TPA_PIN, 0);
ao_gpio_set(MUX_PORT, MUX_BIT, MUX_PIN, 1);
MUX_CONTROL = MUX_STM;
}
void
ao_1802_control_init(void)
{
ao_set_1802();
ao_1802_in(Q_PORT, Q_BIT, q_isr);
(void) MA_set;
(void) DATA_set;
(void) ao_set_arm;
}
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