PIC16C745/765
FIGURE 13-8: WAKE-UP FROM SLEEP THROUGH INTERRUPT
Q1 Q2 Q3 Q4 Q1 Q2 Q3 Q4 Q1
Q1 Q2 Q3 Q4 Q1 Q2 Q3 Q4 Q1 Q2 Q3 Q4 Q1 Q2 Q3 Q4
OSC1
CLKOUT(4)
INT pin
Tost(2)
INTF flag
Interrupt Latency(2)
(INTCON<1>)
GIE bit
Processor in
SLEEP
(INTCON<7>)
INSTRUCTION FLOW
PC
PC
PC+1
PC+2
PC+2
PC + 2
0004h
0005h
Instruction
Inst(0004h)
Inst(PC + 1)
Inst(PC + 2)
Inst(0005h)
Inst(PC) = SLEEP
fetched
Instruction
executed
Dummy cycle
Dummy cycle
SLEEP
Inst(PC + 1)
Inst(PC - 1)
Inst(0004h)
Note 1: HS oscillator mode assumed.
2: TOST = 1024TOSC (drawing not to scale). This delay is not present in EC osc mode.
3: GIE = ’1’ assumed. 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.
The device is placed into a program/verify mode by
holding the RB6 and RB7 pins low, while raising the
MCLR (VPP) pin from VIL to VIHH (see programming
specification). RB6 becomes the programming clock
and RB7 becomes the programming data. Both RB6
and RB7 are Schmitt Trigger inputs in this mode.
13.10 Program Verification/Code Protection
If the code protection bit(s) have not been pro-
grammed, the on-chip program memory can be read
out for verification purposes.
Note: Microchip does not recommend code pro-
tecting windowed devices. Devices that are
code protected may be erased, but not pro-
grammed again.
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. 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).
13.11 ID Locations
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 four least significant bits of the ID
location are used.
FIGURE 13-9: TYPICAL IN-CIRCUIT SERIAL
PROGRAMMING
CONNECTION
13.12 In-Circuit Serial Programming
To Normal
Connections
External
Connector
Signals
PIC16CXX 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 volt-
age. This allows customers to manufacture boards with
unprogrammed devices, and then program the micro-
controller just before shipping the product. This also
allows the most recent firmware or a custom firmware
to be programmed.
PIC16CXX
+5V
0V
VDD
VSS
VPP
MCLR/VPP
RB6
RB7
CLK
Data I/O
VDD
To Normal
Connections
DS41124A-page 108
Advanced Information
1999 Microchip Technology Inc.
MICROCHIP [ MICROCHIP ]
