80C32MODULE
12
______________________________________________________________________________________
______________________80C32 Module
80C32 Module General Description
The Maxim 80C32 microcontroller (C) module is
intended for use with this and other Maxim evaluation
kits (EV kits). It contains the 80C32 C, RS-232 inter-
face, 8kbytes of EPROM, 32kbytes of static RAM, and
address decoding logic. A 40-pin connector mates with
a connector found on Maxim EV kits designed to inter-
face with the 80C32 module.
The module is connected to an IBM-compatible per-
sonal computer over a serial communications port.
Software provided with each EV kit runs on the comput-
er and controls the unit consisting of the 80C32 module
and EV kit. The program uses a routine stored in the
27C64 EPROM to download special 80C32 code for
each kit. The downloaded code controls the EV kit and,
together with the program running on the personal
computer, displays the output data.
The board operates from a single 8V to 22V supply.
Both the pre-regulated and regulated +5V levels are
available to the EV kit through the 40-pin connector.
80C32 Module Power Supply
The Maxim 80C32 module requires an input of 8V to 22V
for normal operation. An on-board 78M05 power regula-
tor supplies the 5V required for the logic on the module,
and any 5V requirements for the EV kit attached to the
40-pin connector. The pre-regulated voltage is also avail-
able on the data connector. The source must be capable
of supplying 100mA for the module and meeting the load
requirements of the EV kit.
Microprocessor Supervisor
A MAX707 on the module monitors the 5V logic supply,
generates the power-on reset, and produces a reset
pulse whenever the reset button is pressed. A watch-
dog function was not included because they frequently
interfere while debugging programs, and debugging is
a prime function of this board.
80C32 Microcontroller
The 80C32 is a member of the popular Intel 8051 family
of Cs. It is a low-power CMOS version that requires
external ROM for program storage, 256 bytes of inter-
nal RAM, and four 8-bit I/O ports. Three of the ports are
required by the system for serial communications and
memory control. The fourth port (P1) is available
through the data connector.
The 80C32 communicates with the PC over a serial RS-
232 link. A MAX233 acts as a level shifter between the
15V RS-232 signals and the TTL levels of the 80C32.
____80C32 Module Component List
DESIGNATION
QTY
DESCRIPTION
C1, C2
2
15pF ceramic capacitors
9
0.1F, 50V ceramic capacitors
C3, C13, C14
3
22F, 16V radial electrolytic
capacitors
D1
1
1N4001 diode
J1
1
40-pin right-angle male connector
J2
1
DB9 right-angle socket
R1
1
620
resistor
RS1
1
10k
10-pin, 9-resistor SIP
SW1
1
Power switch
SW2
1
Reset switch
IC1
1
80C32
IC2
1
MAX233CPP
IC3
1
27C64
IC4
1
74HCT573
IC5
1
74HCT139
IC6
1
74HCT08
IC7
1
74HCT245
IC8
1
IC9
1
78M05
IC10
1
MAX707CPA
Y1
1
11.059MHz crystal
None
1
2-pin power connector
None
1
28-pin 600-mil socket for IC3
(the EPROM)
None
4
Rubber feet
None
1
3.00" x 5.50" PC board
C4, C5, C6, C7,
C8, C9, C10,
C11, C12
62256
Evaluates: MAX186
MAX186 Evaluation System/Evaluation Kit
______________________________________________________________________________________
13
The MAX233 also generates the output voltages neces-
sary to drive RS-232 lines.
Port 0 (pins 32-39) of the 80C32 multiplexes the lower
eight bits of memory address and the eight bits of
read/write data. The lower eight bits of address data
are latched during each I/O cycle by the 74HCT573
octal latch. The latch is controlled by the address latch
enable (ALE) signal of the 80C32. Port 2 (pins 21-28) of
the 80C32 supplies the upper eight bits of address
information.
The port 3 pins (10-17) provide several unrelated func-
tions. Pins 10 and 11 are used as the receive data
(RxD) and transmit data (TxD) pins of the RS-232 link.
Pins 16 and 17 act as the write (
WR
) and read (
RD
) con-
trol signals for the data I/O cycles. Four other pins are
configured as interrupt and timer controls, but are not
used on this board.
Memory
The board has a 27C64 EPROM containing code for ini-
tializing the 80C32 and downloading additional pro-
gram code to the 62256 RAM. After a reset, the EPROM
resident code initializes the 80C32, determines the
address range of the RAM, sets the RS-232 baud rate
to 1200, and waits for communications from the PC.
Receiving any character will prompt the program to
send an initial banner that includes the program name,
revision level, and boundaries of the on-board RAM.
The 62256 CMOS (32kbyte) static RAM is used to hold
program code for the various Maxim EV kits that use
the 80C32 module as the controller. Programs are
transferred from disk to the RAM using software run-
ning on a personal computer, such as MAXLOAD or
other programs provided with Maxim EV kits. Programs
written to execute from this RAM start at 4000 (HEX)
and are typically less than 4kbytes long. The remaining
RAM is available for data storage.
Address Ranges
Logic on the module board generates various enable
signals for different address ranges. The ROM and
RAM enable signals are fed directly to the respective
chips. Several additional signals (CS0-CS3) are avail-
able on the data connector to be used by Maxim EV
kits. Table 1 outlines the address range for each of the
elements found on the 80C32 module.
Table 1. Address Ranges in Hexadecimal
ADDRESS RANGE (HEX)
ENABLE SIGNAL
0000
3FFF
ROM
4000
BFFF
RAM
C000
CFFF
CS0
D000
DFFF
CS1
E000
EFFF
CS2
F000
FFFF
CS3
Data I/O Connector
A 40-pin connector mounted on the edge of the printed
circuit board provides connection between the C
module and other Maxim EV kits. Both power and digi-
tal signals are transferred via the connector. To join the
module board with an EV kit, carefully align and insert
the pins on the connector with the mating 40-pin female
connector of the kit. The pin functions are listed in
Table 2.
Table 2. I/O Connector Pin Functions
PIN
FUNCTION
DESCRIPTION
1-4
Ground
5, 6
Pre-regulator input
7, 8
Regulated +5V
9
RD
Read strobe
10
WR
Write strobe
11
CS0
Address C000-CFFF
12
CS1
Address D000-DFFF
13
CS2
Address E000-EFFF
14
CS3
Address F000-FFFF
15-18
ADDR0-ADDR3
Lowest 4 bits of address
19-26
DB0-DB7
8-bit data bus
27-34
P1.0-P1.7
8 bits of port 1
35-40
Reserved
Evaluates: MAX186
MAX186 Evaluation System/Evaluation Kit
14
______________________________________________________________________________________
Software Architecture
Software for EV kits using the Maxim 80C32 module is
divided into three elements: the interface program run-
ning on an IBM-compatible PC, a module program
located in EPROM, and a program supplied on disk
that is transferred to the RAM located on the module.
EPROM Resident Program
The EPROM resident program initializes the 80C32,
establishes communications over the RS-232 link, ver-
ifies the static RAM, and downloads other programs.
Its operation starts on power-up and whenever the
reset button is pressed. After reset, the program waits
indefinitely to receive a character over the RS-232
port. When the first character is received, a logon
banner identifying the module and firmware revision is
transmitted.
Immediately following transmission of the logon banner,
the program runs a checker routine for the on-board
256kbit static RAM. The RAM is filled with several pat-
terns and then read to verify that each pattern has been
retained. A pass or fail indication is displayed on the
personal computer after each pass. EV kit software
requires proper operation of the RAM. Do not attempt
to use the board if any of the RAM checks fail.
Two other programs for the EV kits are provided on a
floppy disk shipped with each kit. One program acts as
the user interface and transmits commands to the
80C32 module. The other is an 80C32 application pro-
gram that executes from the RAM located on the mod-
ule. The procedure for loading the programs varies with
each kit, so follow the instructions provided.
Evaluates: MAX186
MAX186 Evaluation System/Evaluation Kit
______________________________________________________________________________________
15
Figure 5. 80C32 Module Component Placement Guide (x2)
Evaluates: MAX186
MAX186 Evaluation System/Evaluation Kit
16
______________________________________________________________________________________
Figure 6. 80C32 Module Schematic
1
11
P1.0-P1.7
27-34
1
2
3
4
5
6
7
8
10
11
12
13
14
15
16
17
9
18
19
29
C1 27pF
XX1 11.059MHz
C2
27pF
39
38
37
36
35
34
33
32
30
31
28
27
26
25
24
23
22
21
14
13
12
11
10
9
8
15
0
1
2
3
4
5
6
7
2
3
4
5
6
7
8
9
19
18
17
16
15
14
13
12
D1
D8
Q1
Q8
P1.0
AD0
P1.1
AD1
P1.2
AD2
P1.3
AD3
P1.4
AD4
P1.5
AD5
P1.6
AD6
P1.7
AD7
RXD
ALE
TXD
-EA
-INT0
A15
-INT1
A14
T0
A13
T1
A12
-WR
A11
-RD
A10
RST
-PSEN
XTAL1
A9
XTAL2
A8
0
1
2
3
4
5
6
7
ALL D9 MNEMONICS REFER
TO THE HOST (DTE)
5
GND
1
DCD
4
DTR
6
DSR
2
TXD
3
RXD
7
RTS
8
CTS
5
18
4
19
11
15
10
16
6
T1
OUT
T2
OUT
R1
IN
R2
IN
C2+
C2+
C2-
C2-
GND GND
T1
IN
T2
IN
R1
OUT
R2
OUT
C1+
C1-
V-
V-
V+
2
1
3
20
8
13
12
17
14
9
MAX233A
U2
MAX707
U10
1
2
3
4
V
CC
GND
MR
PFI
RESET
N.C.
RESET
PFO
8
7
6
5
SW1
RESET
U6 HCT08
U6 HCT08
U6 HCT08
U6 HCT08
D
0
1
2
3
4
5
6
7
0
1
2
3
4
5
6
7
74HCT
573
U4
11
12
13
15
16
17
18
19
10
9
8
7
6
5
4
3
O0
O1
O2
O3
O4
O5
O6
O7
A0
A1
A2
A3
A4
A5
A6
A7
+5V
25
24
21
23
2
26
A8
A9
A10
A11
A12
N.C./A13
22
20
C
E
1
27
V
PP
PCM
8
9
10
11
12
13
4
5
6
7
0
1
2
3
A0
A1
EN
2
3
1
14
15
+5V
+5V
U5
HCT139
27C64
U3
9
10
8
12
13
11
4
5
6
1
2
3
2
+5V
+5V
34
27
+5V
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