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Improve read and write timing
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@Andy4495
Andy4495 committed Dec 30, 2023
1 parent 219f16d commit cf7db61
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119 changes: 70 additions & 49 deletions src/AY3891x.cpp
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Original file line number Diff line number Diff line change
Expand Up @@ -3,6 +3,7 @@
https://github.com/Andy4495/AY3891x
12/21/20 - A.T. - Original
29-Dec-2023 - Andy4495 - Release 2.0.0
The AY3891x chip uses an unconventional microcontroller interfacing
method. Instead of using a chip select signal, the chip requires
Expand Down Expand Up @@ -45,9 +46,11 @@
#include "AY3891x.h"

// Constructor with all possible pins
// ****** IMPORTANT! *****
// All three of the bus control signals (BDIR, BC1, BC2) need to be connected
// to the processor.
// Do not use AY3891x::NO_PIN in the constructor for these signals.
// ****** IMPORTANT! *****
AY3891x::AY3891x(byte DA7, byte DA6, byte DA5, byte DA4, byte DA3, byte DA2, byte DA1, byte DA0,
byte BDIR, byte BC2, byte BC1,
byte A9, byte A8,
Expand Down Expand Up @@ -77,9 +80,11 @@ AY3891x::AY3891x(byte DA7, byte DA6, byte DA5, byte DA4, byte DA3, byte DA2, b
// - A9 tied LOW or left unconnected
// - RESET tied high or to an external reset circuit
// - CLOCK connected to an independent clock source
// ****** IMPORTANT! *****
// All three of the bus control signals (BDIR, BC1, BC2) need to be connected
// to the processor.
// Do not use AY3891x::NO_PIN in the constructor for these signals.
// ****** IMPORTANT! *****
AY3891x::AY3891x(byte DA7, byte DA6, byte DA5, byte DA4, byte DA3, byte DA2, byte DA1, byte DA0,
byte BDIR, byte BC2, byte BC1) {

Expand All @@ -101,11 +106,14 @@ AY3891x::AY3891x(byte DA7, byte DA6, byte DA5, byte DA4, byte DA3, byte DA2, b
_chipAddress = 0; // Assume address 0 unless manually changed
}

// ****** IMPORTANT! *****
// For other combinations of pin connections, use the "All pins" constructor
// and use "AY3891::NO_PIN" for pins that are not tied to the microcontroller.
// All three of the bus control signals (BDIR, BC1, BC2) need to be connected
// to the processor.
// Do not use AY3891x::NO_PIN in the constructor for these signals.
// ****** IMPORTANT! *****


void AY3891x::begin() {

Expand All @@ -119,7 +127,11 @@ void AY3891x::begin() {
if (_BDIR_pin != NO_PIN) pinMode(_BDIR_pin, OUTPUT);
if (_BC2_pin != NO_PIN) pinMode(_BC2_pin, OUTPUT);
if (_BC1_pin != NO_PIN) pinMode(_BC1_pin, OUTPUT);
setMode(INACTIVE_000);
//setMode(INACTIVE_010);
// Need to do this one manually since we are in "unknown" state at this point
digitalWrite(_BDIR_pin, LOW);
digitalWrite(_BC2_pin, HIGH);
digitalWrite(_BC1_pin, LOW);

// Set up A8 and A9 to proper levels.
// Pins have internal pullup (A8), or pulldown (A9) so need
Expand All @@ -142,11 +154,17 @@ void AY3891x::latchAddressMode(byte regAddr) {
// 4. Set bus mode to LATCH_ADDR
// 5. Set bus mode to INACTIVE
// Leave DA pins in OUTPUT mode
setMode(INACTIVE_000);

///setMode(INACTIVE_000);
mode010to000();
daPinsOutput(_chipAddress | regAddr); // Register address is 4 lsb
setMode(LATCH_ADDR);
// setMode(LATCH_ADDR);
mode000to001();
// delay is not needed here because code is slow enough (300 ns min per datasheet)
setMode(INACTIVE_000);
// setMode(INACTIVE_000);
mode001to000();
// setMode(INACTIVE_010); // default state is 010
mode000to010();
}

void AY3891x::write(byte regAddr, byte data) {
Expand All @@ -158,15 +176,15 @@ void AY3891x::write(byte regAddr, byte data) {
// 5. Set BC to INACTIVE
// 6. Set BA pins to pinMode INPUT (high impedance)
latchAddressMode(regAddr);
setMode(INACTIVE_010);
daPinsOutput(data);
// The Write Data Pulse Width tDW has a max time of 10 us per the datasheet
// The Write Data Pulse Width tDW has a max time of 10 us per some datasheets
// tDW = time that WRITE_DATA mode is enabled before going back to INACTIVE
if (_BDIR_pin != NO_PIN) {
digitalWrite(_BDIR_pin, HIGH);
digitalWrite(_BDIR_pin, LOW);
}
// setMode(INACTIVE_000); // This is not needed since latchAddressMode() changes to 000
//setMode(WRITE_DATA);
noInterrupts();
mode010to110();
//setMode(INACTIVE_010);
mode110to010();
interrupts();
daPinsInput();
}

Expand All @@ -181,13 +199,13 @@ byte AY3891x::read(byte regAddr) {

latchAddressMode(regAddr);
daPinsInput();
setMode(INACTIVE_010);
setMode(READ_DATA);
///setMode(READ_DATA);
mode010to011();
for (byte i = 0; i < NUM_DA_LINES; i++) {
returnData = returnData | (digitalRead(_DA_pin[i]) << i);
}
setMode(INACTIVE_010);
// setMode(INACTIVE_000); // This is not needed since latchAddressMode() changes to 000
///setMode(INACTIVE_010);
mode011to010();
return returnData;
}

Expand Down Expand Up @@ -264,43 +282,46 @@ byte AY3891x::getChipAddress() {
return _chipAddress;
}

void AY3891x::setMode(byte mode) {
switch (mode) {
case INACTIVE_000: // 0b000
if (_BDIR_pin != NO_PIN) digitalWrite(_BDIR_pin, LOW);
if (_BC2_pin != NO_PIN) digitalWrite(_BC2_pin, LOW);
if (_BC1_pin != NO_PIN) digitalWrite(_BC1_pin, LOW);
break;
// For the following mode change calls, the three
// binary digits represent the following signals:
// BDIR BC2 BC1

case INACTIVE_010: // 0b010
if (_BDIR_pin != NO_PIN) digitalWrite(_BDIR_pin, LOW);
if (_BC2_pin != NO_PIN) digitalWrite(_BC2_pin, HIGH);
if (_BC1_pin != NO_PIN) digitalWrite(_BC1_pin, LOW);
break;
// INACTIVE to LATCH_ADDR
void AY3891x::mode000to001() {
digitalWrite(_BC1_pin, HIGH);
}

case LATCH_ADDR: // 0b001
if (_BDIR_pin != NO_PIN) digitalWrite(_BDIR_pin, LOW);
if (_BC2_pin != NO_PIN) digitalWrite(_BC2_pin, LOW);
if (_BC1_pin != NO_PIN) digitalWrite(_BC1_pin, HIGH);
break;
// LATCH_ADDR to INACTIVE
void AY3891x::mode001to000() {
digitalWrite(_BC1_pin, LOW);
}

case READ_DATA: // 0b011
if (_BDIR_pin != NO_PIN) digitalWrite(_BDIR_pin, LOW);
if (_BC2_pin != NO_PIN) digitalWrite(_BC2_pin, HIGH);
if (_BC1_pin != NO_PIN) digitalWrite(_BC1_pin, HIGH);
break;
// INACTIVE to INACTIVE
void AY3891x::mode000to010() {
digitalWrite(_BC2_pin, HIGH);
}

case WRITE_DATA: // 0b110
if (_BDIR_pin != NO_PIN) digitalWrite(_BDIR_pin, HIGH);
if (_BC2_pin != NO_PIN) digitalWrite(_BC2_pin, HIGH);
if (_BC1_pin != NO_PIN) digitalWrite(_BC1_pin, LOW);
break;
// INACTIVE to INACTIVE
void AY3891x::mode010to000() {
digitalWrite(_BC2_pin, LOW);
}

default:
// Set pins the same as INACTIVE mode 0b000
if (_BDIR_pin != NO_PIN) digitalWrite(_BDIR_pin, LOW);
if (_BC2_pin != NO_PIN) digitalWrite(_BC2_pin, LOW);
if (_BC1_pin != NO_PIN) digitalWrite(_BC1_pin, LOW);
break;
}
// INACTIVE to WRITE_DATA
void AY3891x::mode010to110() {
digitalWrite(_BDIR_pin, HIGH);
}

// WRITE_DATA to INACTIVE
void AY3891x::mode110to010() {
digitalWrite(_BDIR_pin, LOW);
}

// INACTIVE to READ_DATA
void AY3891x::mode010to011() {
digitalWrite(_BC1_pin, HIGH);
}

// READ_DATA to INACTIVE
void AY3891x::mode011to010() {
digitalWrite(_BC1_pin, LOW);
}
14 changes: 13 additions & 1 deletion src/AY3891x.h
View file
Original file line number Diff line number Diff line change
Expand Up @@ -3,6 +3,7 @@
https://github.com/Andy4495/AY3891x
12/21/20 - A.T. - Original
29-Dec-2023 - Andy4495 - Release 2.0.0
*/

Expand Down Expand Up @@ -39,9 +40,11 @@ class AY3891x {

// Constructor for all pins
// Use "AY3891::NO_PIN" for pins that are not tied to the microcontroller.
// ****** IMPORTANT! *****
// All three of the bus control signals (BDIR, BC1, BC2) need to be connected
// to the processor.
// Do not use AY3891x::NO_PIN in the constructor for these signals.
// ****** IMPORTANT! *****
AY3891x(byte DA7, byte DA6, byte DA5, byte DA4, byte DA3, byte DA2, byte DA1, byte DA0,
byte BDIR, byte BC2, byte BC1,
byte A9, byte A8,
Expand All @@ -54,9 +57,11 @@ AY3891x(byte DA7, byte DA6, byte DA5, byte DA4, byte DA3, byte DA2, byte DA1,
// - A9 tied LOW or left unconnected
// - RESET tied high or to an external reset circuit
// - CLOCK connected to an independent clock source
// ****** IMPORTANT! *****
// All three of the bus control signals (BDIR, BC1, BC2) need to be connected
// to the processor.
// Do not use AY3891x::NO_PIN in the constructor for these signals.
// ****** IMPORTANT! *****
AY3891x(byte DA7, byte DA6, byte DA5, byte DA4, byte DA3, byte DA2, byte DA1, byte DA0,
byte BDIR, byte BC2, byte BC1);

Expand All @@ -80,7 +85,14 @@ AY3891x(byte DA7, byte DA6, byte DA5, byte DA4, byte DA3, byte DA2, byte DA1,
void daPinsInput();
void daPinsOutput(byte data);
void latchAddressMode(byte regAddr);
void setMode(byte mode);
inline void mode000to001();
inline void mode001to000();
inline void mode000to010();
inline void mode010to000();
inline void mode010to110();
inline void mode110to010();
inline void mode010to011();
inline void mode011to010();
};

#endif

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