RFPIC12F675 Datasheet, PDF (71/136 Pages) Microchip Technology – FLASH-Based Microcontroller with ASK/FSK Transmitter

rfPIC12F675
FIGURE 10-14:
TYPICAL IN-CIRCUIT
SERIAL PROGRAMMING
CONNECTION
External
Connector
Signals
+5V
0V
VPP
CLK
Data I/O
To Normal
Connections
rfPIC12F675
VDD
VSS
GP3/MCLR/VPP
GP1
GP0
VDD
To Normal
Connections
FIGURE 10-15:
PARALLEL DIP SOCKET
FOR EMULATION
1
8
2
7
3
6
4
5
VDD
GP5
GP4
GP3
VSS
GP0
GP1
GP2
10.10 In-Circuit Serial Programming
The rfPIC12F675 microcontrollers can be serially
programmed while in the end application circuit. This is
done with two lines for clock and data, and three lines
for power, ground, and programming voltage.
This allows customers to manufacture boards with
unprogrammed devices, and then program the
microcontroller before shipping the product. This also
allows the most recent firmware or custom firmware to
be programmed.
The device is placed into a Program/Verify mode by
holding the GP0 and GP1 pins low, while raising the
MCLR (VPP) pin from VIL to VIHH (see Programming
Specification). GP0 becomes the programming data
and GP1 becomes the programming clock. Both GP0
and GP1 are Schmitt Trigger inputs in this mode.
After RESET, to place the device into Programming/
Verify mode, the program counter (PC) is at location
00h. A 6-bit command is then supplied to the device.
Depending on the command, 14-bits of program data
are then supplied to or from the device, depending on
whether the command was a load or a read. For
complete details of serial programming, please refer to
the Programming Specifications document.
A typical In-Circuit Serial Programming connection is
shown in Figure 10-14. The programming connections
are isolated from conflicting outputs and capacitive
loads by the 3 resistors. The VDD connection on MCLR
may not be required if the pin is configured as GP3. Do
not place sensitive circuitry on the GP3/MCLR pin
without protection since the VPP signal goes well above
VDD during programming.
10.11 In-Circuit Debugging
Since in-circuit debugging requires the loss of clock,
data and MCLR pins, MPLAB^® ICD 2 development with
an 8-pin microcontroller is not practical. Since the
MPLAB ICE 2000 emulation module leads would be
too long for the RF signals the following debug/emula-
tion strategy is recommended.
Build a prototype board with all your digital, analog, and
RF circuitry. Add an 8 pin DIP socket for the PIC12F675
debugging. Connect the socket as shown in Figure 10-
15. When soldering the rfPIC12F675 down bend up
pins 1-4 and 17-20 so that they do not contact the
board. A PIC12F675 or emulation/debugging develop-
ment tool can be plugged into the socket as in
Figure 10-16.
This test method encourages RF development to start
early, as soon as the firmware can toggle the RF enable
and data lines. The socket can even be left in the final
layout for in-circuit production programming. A simple
method for programming is to solder all the
rfPIC12F675 pins to the board and move the 8-pin DIP
socket to the back side of the board. Then use the 8-pin
standoff from the MPLAB ICE 2000 emulator to
connect the PCB to a programmer such as the Pro
Mate^® II or PICkit™ 1 as in Figure 10-17.
There is an ICD 2 header inteface board for the
PIC12F675, part number AC162050. This special ICD
module is mounted on the top of a header and its
 2003-2013 Microchip Technology Inc.
Preliminary
DS70091B-page 71