kimdaihai / grblesp

GRBL ported to ESP8266, using up to 8 axis. No arduino involved

GRBLESP

Implements the latest version of GRBL using ESP8266 only. To overcome the problem of the lack of pins, it uses SPI to drive 4 shift registers of 8 bits each.

The aim of having 32 pins is to be able to handle up to 8 axis.

• GPIO0 controls inputs as RESET, FEED_HOLD, START_CYCLE and SAFETY_DOOR

• GPIO2 controls all limits switches

• GPIO12 remains unused (because it functions as SPI HMISO)

• GPIO13 sends data to the shift registers (SPI HMOSI)

• GPIO14 clock signal for the shift registers (SPI HSCLK)

• GPIO15 serves as CHIP_SELECT for the SPI

The board should use 4 x 8-bit shift registers. They are arranged this way:

• 8 bits for step pins

• 8 bits for direction pins

• 8 bits for Misc, inputs and outputs, following this structure (although it might change still a bit):
  #define CONTROL_RESET_BIT 0
  #define CONTROL_FEED_HOLD_BIT 1
  #define CONTROL_CYCLE_START_BIT 2
  #define CONTROL_SAFETY_DOOR_BIT 3
  #define PROBE_BIT 4
  #define COOLANT_FLOOD_BIT 5
  #define COOLANT_MIST_BIT 6
  #define SPINDLE_ENABLE_BIT 7

• 8 bits for limits. All inputs

Probe, spindle, and probably other features, are not yet supported

J4

Pin	Function	Type
1	STEP X	(output)
2	STEP Y	(output)
3	STEP Z	(output)
4	STEP A	(output)
5	STEP B	(output)
6	STEP C	(output)
7	STEP D	(output)
8	STEP E	(output)

J3

Pin	Function	Type
1	DIR X	(output)
2	DIR Y	(output)
3	DIR Z	(output)
4	DIR A	(output)
5	DIR B	(output)
6	DIR C	(output)
7	DIR D	(output)
8	DIR E	(output)

J2

Pin	Function	Type
1	RESET	(input)
2	FEED HOLD	(input)
3	CYCLE START	(input)
4	SAFETY DOOR	(input)
5	PROBE	(input)
6	COOLANT/FLOOD	(output)
7	COOLANT/MIST	(output)
8	SPINDLE	(output)

J1

Pin	Function	Type
1	LIMIT X	(input)
2	LIMIT Y	(input)
3	LIMIT Z	(input)
4	LIMIT A	(input)
5	LIMIT B	(input)
6	LIMIT C	(input)
7	LIMIT D	(input)
8	LIMIT E	(input)