PIC16C923-04I/CL Microchip Technology, PIC16C923-04I/CL Datasheet - Page 118

• Manufacturer Part Number: PIC16C923-04I/CL
• Description: 8-Bit CMOS Microcontroller with LCD Driver
• Manufacturer: Microchip Technology

PIC16C9XX
FIGURE 14-18:WAKE-UP FROM SLEEP THROUGH INTERRUPT
14.9
If the code protection bit(s) have not been pro-
grammed, the on-chip program memory can be read
out for verification purposes.
14.10
Four memory locations (2000h - 2003h) are designated
as ID locations where the user can store checksum or
other code-identification numbers. These locations are
not accessible during normal execution but are read-
able and writable during program/verify. It is recom-
mended that only the 4 least significant bits of the ID
location are used.
14.11
PIC16CXXX microcontrollers can be serially pro-
grammed 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 unprogrammed devices, and then program the
microcontroller just before shipping the product. This
also allows the most recent firmware or a custom firm-
ware to be programmed.
The device is placed into a program/verify mode by
holding the RB6 and RB7 pins low while raising the
MCLR (V
specification). RB6 becomes the programming clock
and RB7 becomes the programming data. Both RB6
and RB7 are Schmitt Trigger inputs in this mode.
DS30444E - page 118
Note
Note:
INSTRUCTION FLOW
INTF flag
(INTCON<1>)
GIE bit
(INTCON<7>)
Instruction
fetched
Instruction
executed
CLKOUT(4)
INT pin
1: XT, HS or LP oscillator mode assumed.
2: T
3: GIE = '1' assumed. In this case after wake- up, the processor jumps to the interrupt routine. If GIE = '0', execution will continue in-line.
4: CLKOUT is not available in these osc modes, but shown here for timing reference.
OSC1
Program Verification/Code Protection
ID Locations
PP
PC
In-Circuit Serial Programming
Microchip does not recommend code pro-
tecting windowed devices.
OST
) pin from V
Inst(PC) = SLEEP
Q1 Q2 Q3 Q4
= 1024T
Inst(PC - 1)
PC
OSC
IL
(drawing not to scale) This delay will not be there for RC osc mode.
to V
Q1 Q2 Q3 Q4
Inst(PC + 1)
SLEEP
PC+1
IHH
(see programming
Q1
Processor in
SLEEP
PC+2
T
OST
(2)
Q1 Q2 Q3 Q4 Q1 Q2 Q3 Q4
Inst(PC + 2)
Inst(PC + 1)
After reset, to place the device into program/verify
mode, the program counter (PC) is at location 00h. A
6-bit command is then supplied to the device. Depend-
ing on the command, 14-bits of program data are then
supplied to or from the device, depending if the com-
mand was a load or a read. For complete details of
serial programming, please refer to the PIC16C6X/7X
Programming Specifications (Literature #DS30228).
FIGURE 14-19:TYPICAL IN-CIRCUIT SERIAL
PC+2
External
Connector
Signals
Data I/O
CLK
+5V
V
0V
PP
Interrupt Latency
Dummy cycle
(Note 2)
PC + 2
PROGRAMMING
CONNECTION
To Normal
Connections
To Normal
Connections
Q1 Q2 Q3 Q4
1997 Microchip Technology Inc.
Inst(0004h)
Dummy cycle
0004h
V
V
MCLR/V
RB6
RB7
Q1 Q2 Q3 Q4
DD
SS
PIC16CXXX
Inst(0005h)
Inst(0004h)
0005h
V
PP
DD