Datasheet
2010 Microchip Technology Inc. DS39622L-page 13
PIC18F2XXX/4XXX FAMILY
FIGURE 2-15: TABLE WRITE, POST-INCREMENT TIMING (1101)
2.8 Dedicated ICSP/ICD Port
(44-Pin TQFP Only)
The PIC18F4455/4458/4550/4553 44-pin TQFP
devices are designed to support an alternate
programming input: the dedicated ICSP/ICD port. The
primary purpose of this port is to provide an alternate
In-Circuit Debugging (ICD) option and free the pins
(RB6, RB7 and MCLR
) that would normally be used for
debugging the application. In conjunction with ICD
capability, however, the dedicated ICSP/ICD port also
provides an alternate port for ICSP.
Setting the ICPRT Configuration bit enables the
dedicated ICSP/ICD port. The dedicated ICSP/ICD
port functions the same as the default ICSP/ICD port;
however, alternate pins are used instead of the default
pins. Table 2-10 identifies the functionally equivalent
pins for ICSP purposes:
The dedicated ICSP/ICD port is an alternate port. Thus,
ICSP is still available through the default port even
though the ICPRT Configuration bit is set. When the
V
IH is seen on the MCLR/VPP/RE3 pin prior to applying
V
IH to the ICRST/ICVPP pin, then the state of the
ICRST/ICV
PP pin is ignored. Likewise, when the VIH is
seen on ICRST/ICV
PP prior to applying VIH to MCLR/
V
PP/RE3, then the state of the MCLR/VPP/RE3 pin is
ignored.
TABLE 2-10: ICSP™ EQUIVALENT PINS
1234
PGC
P5
PGD
PGD = Input
5678
1
234
P5A
9
10 11 13 15 161412
Fetch Next 4-Bit Command
1011
1234
nnnn
P3
P2
P2A
000000 010001111 0
04C3
P4
4-Bit Command 16-Bit Data Payload
P2B
Note: The ICPRT Configuration bit can only be
programmed through the default ICSP
port. Chip Erase functions through the
dedicated ICSP/ICD port do not affect this
bit.
When the ICPRT Configuration bit is set
(dedicated ICSP/ICD port enabled), the
NC/ICPORTS pin must be tied to either
V
DD or VSS.
The ICPRT Configuration bit must be
maintained clear for all 28-pin and 40-pin
devices; otherwise, unexpected operation
may occur.
Pin Name
During Programming
Pin Name Pin Type Dedicated Pins Pin Description
MCLR/VPP/RE3 VPP P NC/ICRST/ICVPP Programming Enable
RB6 PGC I NC/ICCK/ICPGC Serial Clock
RB7 PGD I/O NC/ICDT/ICPGD Serial Data
Legend: I = Input, O = Output, P = Power