# Fast and extensible matrix.c
This matrix.c is faster and more extensible than the standard quantum/matrix.c.
* The execution speed of the `matrix_scan()` function is several times faster than quantum/matrix.c.
* In addition to handling MCU GPIOs, it can be extended to handle I/O extenders.
## ToDo list
- [x] support Pro Micro
- [x] support Proton-C
- [x] support DIRECT_PINS
- [x] support DIODE_DIRECTION == ROW2COL
- [x] support 74HC157: quadruple 2-line to 1-line data selectors / multiplexers
- [x] support 74HC153: dual 4-line to 1-line data selectors / multiplexers
- [ ] support I/O expander (MCP23018)
- [ ] support MCU & I/O expander (MCP23018) mixture like ErgoDox
## Current performance
| MCU | delay type | execution time
of
`matrix_scan()` | matrix scan rate |
|-------------------|---------------|------------|-----------------|
| Pro Micro (16MHz) | fast adaptive | 75.6us | 8090 scans/sec |
| Proton C (72MHz) | fast adaptive | 49.8us | 15100 scans/sec |
## Configuration
This matrix.c requires a different configuration than quantum/matrix.c.
### Output pins configuration
The output pins is the Row pins if `DIODE_DIRECTION == COL2ROW`, and the Col pins if `DIODE_DIRECTION == ROW2COL`. When DIRECT_PINS is defined, the output pins do not need to be set.
Example:
```c
// list of OUTPUT(row) ports
#define MATRIX_OUT_PORTS \
(Port_D, MCU_GPIO, D0), \
(Port_C, MCU_GPIO, C0), \
(Port_E, MCU_GPIO, E0), \
(Port_B, MCU_GPIO, B0)
// list of OUTPUT pins
#define MATRIX_OUT_PINS \
(0, Port_D, 4), \
(1, Port_C, 6), \
(2, Port_D, 7), \
(3, Port_E, 6), \
(4, Port_B, 4), \
(5, Port_B, 5)
```
### Input pins configuration
The input pins is the Col pins if `DIODE_DIRECTION == COL2ROW`, and the Row pins if `DIODE_DIRECTION == ROW2COL`. When DIRECT_PINS is defined, the input pin settings will enumerate the connection pins of all switches.
Example:
```c
// list of INPUT ports
#define MATRIX_IN_PORTS (Port_F, MCU_GPIO, F0), (Port_B, MCU_GPIO, B0)
// list of INPUT pins
#define MATRIX_IN_PINS \
(0, Port_F, 4), \
(1, Port_F, 5), \
(2, Port_F, 6), \
(3, Port_F, 7), \
(4, Port_B, 1), \
(5, Port_B, 3)
```
### Multiplexer Extension
By defining the `MATRIX_EXTENSION_74HC157` macro or `MATRIX_EXTENSION_74HC153` macro, you can connect a multiplexer to the GPIO to extend the input pins.
Example:
```c
#define MATRIX_EXTENSION_74HC157 B2 /* or #define MATRIX_EXTENSION_74HC153 B2, B6 */
// list of OUTPUT ports
#define MATRIX_OUT_PORTS (Port_D, MCU_GPIO, D0), (Port_C, MCU_GPIO, C0), (Port_E, MCU_GPIO, E0), (Port_B, MCU_GPIO, B0)
// list of OUTPUT pins
#define MATRIX_OUT_PINS (0, Port_D, 4), (1, Port_C, 6), (2, Port_D, 7), (3, Port_E, 6), (4, Port_B, 4), (5, Port_B, 5)
// list of INPUT ports
#define MATRIX_IN_PORTS \
(Port_Fa, MCU_GPIOa, F0), \
(Port_Ba, MCU_GPIOa, B0), \
(Port_Fb, MCU_GPIOb, F0), \
(Port_Bb, MCU_GPIOb, B0)
// list of INPUT pins
#define MATRIX_IN_PINS \
(0, Port_Fa, 4), \
(1, Port_Fb, 5), \
(2, Port_Fb, 6), \
(3, Port_Fa, 7), \
(4, Port_Ba, 1), \
(5, Port_Bb, 3)
```
### I/O expander Extension
I plan to provide extensions to support I/O expanders such as MCP23018 and PCA9555.
## Compile
* Measure the execution time of matrix_scan()
* `make MTEST=matrix_debug_scan[,..] handwired/symmetric70_proto/promicro/fast:default:flash`
* Measure delay time.
* `make MTEST=matrix_debug_delay[,..] handwired/symmetric70_proto/promicro/fast:default:flash`
## Measurement result
### Pro Micro (ATmega32u4 16Mhz)
#### Default setting (show `matrix_scan()` time)
- `make MTEST=matrix_debug_scan handwired/symmetric70_proto/promicro/fast:default:flash`
- CH1: Row 0
- CH2: Row 1
- CH3: Row 4
- CH4: matrix_scan()
- Execution time of matrix_scan() 75.6us
- Frequency of matrix scan 8.09kHz (123.6us)
#### Default setting (show delay time)
- `make MTEST=matrix_debug_delay handwired/symmetric70_proto/promicro/fast:default:flash`
##### Press R0C0 key
- CH1: Row 0
- CH2: Row 1
- CH3: Row 4
- CH4: delay time
- Frequency of matrix scan 7.84kHz (127.6us)
### Proton C
#### Default setting (show `matrix_scan()` time)
- `make MTEST=matrix_debug_scan handwired/symmetric70_proto/proton_c/fast:default:flash`
- CH1: Row 0
- CH2: Row 1
- CH3: Row 4
- CH4: matrix_scan()
- Execution time of matrix_scan() 49.8us
- Frequency of matrix scan 15.1kHz (66.2.6us)
#### Default setting (show delay time)
- `make MTEST=matrix_debug_delay handwired/symmetric70_proto/proton_c/fast:default:flash`
##### Press R0C0 key
- CH1: Row 0
- CH2: Row 1
- CH3: Row 4
- CH4: delay time
- Frequency of matrix scan 13.9kHz (71.8us)
##### Connect a 500pF capacitor between C0 line and GND, Press R0C0, R1C0, R2C0, R3C0, R4C0 keys
- CH1: Row 0
- CH2: Row 1
- CH3: Col 0
- CH4: delay time
- Delay time 11.6us
- Threshold Voltage 1.9V
##### Connect a 1000pF capacitor between C0 line and GND, Press R0C0, R1C0, R2C0, R3C0, R4C0 keys
- CH1: Row 0
- CH2: Row 1
- CH3: Col 0
- CH4: delay time
- Delay time 18.6us
- Threshold Voltage 1.9V
