The IRTC ISP is a Microchip programmer and Forth development interface. ASCII command codes are used to specify the functions required and serial data from the PC is converted into Clock and Data signals to program and interrogate the PIC.
The ISP is powered from the target system and requires the following connections to the target processor;
Header Signal Connector 6 way
Pin1 - VCC +3.3 - 5.0 Volts
Pin2 - GND 0 Volts
Pin3 - RB7 should have a pull-up resistor of >22K
Pin4 - RB6 should have a pull-up resistor of >22K
Pin5 - RB5 should have a pull-down resistor of >22K
Pin6 - RESET Target CPU Reset with a pull-up resistor of 10K
The ISP must also be connected to one of the host computers serial ports. The .INI files are set to COM1.
The Target and the ISP should be powered up together to ensure they reset properly. It is also important that the ISP is connected to an operating serial port with PC running prior to power-up.
Below are the IRTC words to set the PIC configuration. ONLY the first three configuration registers are modified by SET-CONFIG
NOTE: The configuration setting words below may change depending on the device. Refer to the register file for the device you are using.
CONFIG1 - CF1
OSCEN-ON
OSCEN-OFF
LP-OSC
XT-OSC
HS-OSC
RC-OSC
RC-OSC+OSC/4
EC-OSC+OSC=RA6
HS-OSC+PLL
RC-OSC+OSC=RA6
CONFIG2 - CF2
BROWN-OUT-4V5
BROWN-OUT-4V2
BROWN-OUT-2V7
BROWN-OUT-2V0
BROWN-OUT-ON
BROWN-OUT-OFF
PWRT-OUT-ON
PWRT-OUT-OFF
CONFIG3 - CF3
WDT-OUT-ON
WDT-OUT-OFF
The rest of the configuration registers for the memory protection may be set with;
mask CONFIGx CONFIG!
Note: Any unused bits in the mask should be set high, 1, or the result may not be as you expect. Also CONFIG! programs both high and low parts of the configutation address.