Microchip Technology IC MCU OTP 4K PIC16C74B-20/L PLCC-44 MCP PIC16C74B-20/L 数据表
产品代码
PIC16C74B-20/L
PIC16C63A/65B/73B/74B
DS30605D-page 98
1998-2013 Microchip Technology Inc.
FIGURE 13-7:
WAKE-UP FROM SLEEP THROUGH INTERRUPT
13.9
Program Verification/Code
Protection
Protection
If the code protection bit(s) have not been pro-
grammed, the on-chip program memory can be read
out for verification purposes.
grammed, the on-chip program memory can be read
out for verification purposes.
13.10 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.
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.
13.11 In-Circuit Serial Programming
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
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.
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
holding the RB6 and RB7 pins low, while raising the
MCLR (V
PP
) pin from V
IL
to V
IHH
(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.
and RB7 becomes the programming data. Both RB6
and RB7 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 if the
command was a load or a read. For complete details of
serial programming, please refer to the PIC16C6X/7X
Programming Specifications (Literature #DS30228).
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 if the
command was a load or a read. For complete details of
serial programming, please refer to the PIC16C6X/7X
Programming Specifications (Literature #DS30228).
FIGURE 13-8:
TYPICAL IN-CIRCUIT
SERIAL PROGRAMMING
CONNECTION
SERIAL PROGRAMMING
CONNECTION
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
INTF Flag
(INTCON<1>)
(INTCON<1>)
GIE bit
(INTCON<7>)
(INTCON<7>)
INSTRUCTION FLOW
PC
Instruction
Fetched
Fetched
Instruction
Executed
Executed
PC
PC+1
PC+2
Inst(PC) = SLEEP
Inst(PC - 1)
Inst(PC + 1)
SLEEP
Processor in
SLEEP
Interrupt Latency
(2)
Inst(PC + 2)
Inst(PC + 1)
Inst(0004h)
Inst(0005h)
Inst(0004h)
Dummy cycle
PC + 2
0004h
0005h
Dummy cycle
T
OST
(2)
PC+2
Note
1:
XT, HS or LP oscillator mode assumed.
2:
T
OST
= 1024Tosc (drawing not to scale). This delay is not present in RC 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.
Note:
Microchip does not recommend code pro-
tecting windowed devices. Devices that
are code protected may be erased, but not
programmed again.
tecting windowed devices. Devices that
are code protected may be erased, but not
programmed again.
External
Connector
Signals
Connector
Signals
To Normal
Connections
Connections
To Normal
Connections
Connections
PIC16CXX
V
DD
V
SS
MCLR/V
PP
RB6
RB7
+5V
0V
V
PP
CLK
Data I/O
V
DD