/** @file icsp.h
 * 
 * This part of the firmware implements the ICSP interface by bitbanging some
 * GPIO pins.
 * 
*/

#ifndef _icsp_h_
#define _icsp_h_

// ICSP Pin Configuration
#define ICSP_PIN_MCLR   (1 << 1)
#define ICSP_PIN_CLK    (1 << 2)
#define ICSP_PIN_DAT    (1 << 3)
#define ICSP_PORT       PORTA
#define ICSP_DDR        DDRA
#define ICSP_PIN        PINA

// ICSP Commands
// #define ICSP_CMD_ADDR_LOAD 0x80
// #define ICSP_CMD_ERASE_BULK 0x18
// #define ICSP_CMD_ERASE_ROW 0xF0
// #define ICSP_CMD_LOAD_DATA_INC 0x02
// #define ICSP_CMD_LOAD_DATA 0x00
// #define ICSP_CMD_READ_DATA_INC 0xFE
// #define ICSP_CMD_READ_DATA 0xFC
// #define ICSP_CMD_ADDR_INC 0xF8
// #define ICSP_CMD_START_INT 0xE0
// #define ICSP_CMD_START_EXT 0xC0
// #define ICSP_CMD_STOP_EXT 0x82

// Startup bit sequence to enter programming mode is cleverly MCHIP in ascii.=
#define ICSP_STARTUP_KEY "MCHP"

// ICSP Timings
#define ICSP_DELAY_ENTH 250         // Programming Mode Entry Hold Time
#define ICSP_DELAY_CKL 3            // Clock Low Pulse Width
#define ICSP_DELAY_CKH 3            // Clock High Pulse Width
#define ICSP_DELAY_DLY 3            // Data input not driven to Next Clock Input
#define ICSP_DELAY_ERAB 9464        // Bulk erase cycle time
#define ICSP_DELAY_ERAR 3000        // Row erase cycle time (Sector erase cycle time)
#define ICSP_DELAY_PINT_PM 3000     // Program memory internally timed
#define ICSP_DELAY_PINT_CW 5800     // Configuration word internally timed (EEPROM)


/** Initialize the ICSP pins. */
void        icsp_init (void);

/** Enter the connected chip into ICSP programming mode by shifiting in the sequence MSB first. */
void        icsp_enable_msb (void);

/** Enter the connected chip into ICSP programming mode by shifiting in the sequence LSB first. */
void        icsp_enable_lsb (void);

/** Exit the connected chip from ICSP programming mode. */
void        icsp_disable (void);

/** Send ICSP command to the connected chip. */
void        icsp_command (unsigned char command);

/** Send ICSP payload to the connected chip. */
void        icsp_payload (unsigned long payload);

/** Read an incoming data payload from the connected chip. */
unsigned long icsp_read (void);


/** Send 6-bit ICSP command to the connected chip. */
void        icsp_short_command (unsigned char command);

/** Send 6-bit ICSP command with 16-bit payload to the connected chip. */
void        icsp_short_payload (unsigned int payload);

/** Send 6-bit ICSP command then read an incoming 16-bit data payload from the connected chip. */
unsigned int icsp_short_read (void);


#endif