SHARP PC-G850V(S) User Manual -
Appendix A: 11-Pin Interface
17
PIC-Mode
The PIC-mode of the PC-G850V(S) is used for the transfer of an assembled PIC-
program to a PIC microcontroller. This process is called PIC-programming, PIC-program
(up)loading or PIC-burning, since a specific “burning” voltage is needed that is much
higher than normal operating voltage. This mode is activated by the PIC-loader menue
item in the PIC-assembler sub-menue only. The PC-G850V(S) supports the ICSP-
protocol (In-Circuit Serial Programming) of the PIC16F8x microcontroller family and
compatible models.
The pin-out and signal semantics of the 11-pin interface in PIC-mode is as follows:
Pin
#
Signal
Direction Semantics
4
CP
Out
This signal controls the ICSP-programming mode of the
PIC. If this signal is HIGH, the burning voltage (+12 to
+14V) must be provided at the MCLR#-pin of the PIC.
If this signal is LOW, the MCLR#-pin must be at GND-
level or VDD (+5V).
5
CLK#
Out
This signal provides the ICSP-clock-pulse for the PIC to
be programmed. However the inverted CLK# (i.e. CLK)
signal must be provided at the RB6-input-pin of the PIC.
The latter latches data bits on the falling edge of that
CLK-pulse.
6
DATAIN
In
This input must be connected with the RB7-pin of the
PIC. Data is read from the PIC over this line for
verification of the programming process.
7
DATAOUT
Out
This output is used for serial data and command transfer
to the PIC in ICSP-mode. It has to be connected with the
RB7-pin of the PIC too.
8
LOWBATT# In
This digital input can be connected to a programming
voltage monitoring circuit (esp. when using an external
supply). LOW (logic 0) means „weak voltage supply“.
Due to the specification of the PIC16F8x family, the PIC performs a transition to ICSP-
mode, if and only if all of the following conditions are true:
•
VDD = +5V, VSS = GND
•
MCLR# = +12V to +14V
•
RB6 (CLK) = LOW.
•
RB7 (DATA) = LOW.
