RFPIC12C509AG Datasheet, PDF (57/104 Pages) Microchip Technology – 18/20-Pin 8-Bit CMOS Microcontroller with UHF ASK/FSK Transmitter

rfPIC12C509AG/509AF
8.11 In-Circuit Serial Programming
The rfPIC12C509AG/509AF microcontroller with
EPROM program memory can be serially programmed
while in the end application circuit. This is simply done
with two lines for clock and data, and three other lines
for power, ground, and the programming voltage. This
allows customers to manufacture boards with unpro-
grammed devices, and then program the microcontrol-
ler just before shipping the product. This also allows the
most recent firmware or a custom firmware to be pro-
grammed.
The device is placed into a program/verify mode by
holding the GP1 and GP0 pins low while raising the
MCLR (VPP) pin from VIL to VIHH (see programming
specification). GP1 becomes the programming clock
and GP0 becomes the programming data. Both GP1
and GP0 are Schmitt Trigger inputs in this mode.
After RESET, a 6-bit command is then supplied to the
device. Depending on the command, 14-bits of pro-
gram data are then supplied to or from the device,
depending if the command was a load or a read. For
complete details of serial programming, please refer to
the PIC12C5XX Programming Specifications.
A typical in-circuit serial programming connection is
shown in Figure 8-14.
FIGURE 8-14:
TYPICAL IN-CIRCUIT
SERIAL PROGRAMMING
CONNECTION
External
Connector
Signals
+5V
0V
VPP
CLK
Data I/O
To Normal
Connections
rfPIC12C509AG/
509AF
VDD
VSS
MCLR/VPP
GP1
GP0
VDD
To Normal
Connections
© 2001 Microchip Technology Inc.
Preliminary
DS70031A-page 55