PIC17CXX Datasheet, PDF (1/16 Pages) Microchip Technology – EPROM Memory Programming Specification

PIC17CXX
EPROM Memory Programming Specification
This document includes the programming
specifications for the following devices:
• PIC17C42
• PIC17C43
• PIC17C42A
• PIC17CR43
• PIC17CR42
• PIC17C44
1.0 PROGRAMMING THE PIC17CXX
The PIC17CXX is programmed using the TABLWT
instruction. The table pointer points to the internal
EPROM location start. Therefore, a user can program
an EPROM location while executing code (even from
internal EPROM). This programming specification
applies to PIC17CXX devices in all packages.
For the convenience of a programmer developer, a
“program & verify” routine is provided in the on-chip test
program memory space, the program resides in ROM
and not EPROM. Therefore, it is not erasable. The
“program/verify” routine allows the user to load any
address, program a location, verify a location or incre-
ment to the next location. It allows variable program-
ming pulse width.
1.1 Hardware Requirements
Since the PIC17CXX under programming is actually
executing code from “boot ROM,” a clock must be pro-
vided to the part. Furthermore, the PIC17CXX under
programming may have any oscillator configuration
(EC, XT, LF or RC). Therefore, the external clock driver
must be able to overdrive pulldown in RC mode. CMOS
drivers are required since the OSC1 input has a
Schmitt trigger input with levels (typically) of 0.2VDD
and 0.8VDD. See the PIC17C4X data sheet
(DS30412A) for exact specifications.
Pin Diagram
40L PDIP, Windowed CERDIP
VDD
1
40
RC0/AD0
2
39
RC1/AD1
3
38
RC2/AD2
4
37
RC3/AD3
5
36
RC4/AD4
6
35
RC5/AD5
7
34
RC6/AD6
8
33
RC7/AD7
9
32
VSS
10
31
RB0/CAP1
11
30
RB1/CAP2
12
29
RB2/PWM1
13
28
RB3/PWM2
14
27
RB4/TCLK12
15
26
RB5/TCLK3
16
25
RB6
17
24
RB7
18
23
OSC1/CLKIN
19
22
OSC2/CLKOUT
20
21
RD0/AD8
RD1/AD9
RD2/AD10
RD3/AD11
RD4/AD12
RD5/AD13
RD6/AD14
RD7/AD15
MCLR/VPP
VSS
RE0/ALE
RE1/OE
RE2/WR
TEST
RA0/INT
RA1/T0CKI
RA2
RA3
RA4/RX/DT
RA5/TX/CK
The PIC17CXX requires two programmable power
supplies, one for VDD (2.5V to 6.0V recommended) and
one for VPP (13 ± 0.25V). Both supplies should have a
minimum resolution of 0.25V.
The PIC17CXX uses an intelligent algorithm. The algo-
rithm calls for program verification at VDDmin as well as
VDDmax. Verification at VDDmin guarantees good
“erase margin”. Verification at VDDmax guarantees
good “program margin”. Three times (3X) additional
pulses will increase program margin then beyond VDD
(max.) and insure safe operation in user system.
PIN DESCRIPTIONS (DURING PROGRAMMING): PIC17C42/42A/43/44
During Programming
Pin Name
Pin Name
RA <0:4>
RA <0:4>
TEST
TEST
RB <7:0>
PAD <15:8>
RC <7:0>
PAD <7:0>
MCLR/VPP
VPP
VDD
VDD
VSS
VSS
Legend: I = Input, O = Output, P = Power
Pin Type
I
I
I/O
I/O
P
P
P
Pin Description
Necessary in programming mode
Must be set to “high” to enter programming mode
Address & data: high byte
Address & data: low byte
Programming Power
Power Supply
Ground
1996 Microchip Technology Inc.
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