68HC16 Module

________________General Description

The 68HC16 module is an assembled and tested print-
ed-circuit board intended for use with Maxim's high-
speed serial-interface evaluation kits (EV kits). The
module uses an inexpensive 8-bit implementation of
Motorola's MC68HC16Z1 microcontroller (礐) to collect
data samples at high speed using the QSPITM interface.
It requires an IBM-compatible personal computer and
an external DC power supply, typically 12V DC or as
specified in EV kit manual.

Maxim's 68HC16 module is provided to allow customers
to evaluate selected Maxim products. It is not intended
to be used as a microprocessor development platform,
and such use is not supported by Maxim.

QSPI is a trademark of Motorola Corp.

68HC16 Module

________________Detailed Description

Power Input Connector J2

The 68HC16 module draws its power from a user-sup-
plied power source connected to terminal block J2. Be
sure to note the positive and negative markings on the
board. A three-terminal 5V regulator allows input voltages
between 8V and an absolute maximum of 20V. The
68HC16 module typically requires 200mA of input current.

68HC16 Microcontroller

U1 is Motorola's 68HC16Z1 礐. Contact Motorola for 礐
information, development, and support. Maxim EV kits use
the high-speed queued serial peripheral interface (QSPI)
and the internal chip-select generation.

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.

Right-angle printed circuit board
mount, DB9 female socket

2-circuit terminal block

40-pin right-angle male connector

1N4001 diode

0.1礔 capacitors

C10瑿14

Reference designator, not used

0.01礔 capacitor

22pF capacitors

C6, C7

22礔, 25V radial-lead electrolytic
capacitors

C4, C5

1礔 ceramic capacitors

C1, C2, C3

DESCRIPTION

QTY

DESIGNATION

10M

, 5% resistor

Light-emitting diode

LED1

Open

JU5

Open

JU4

Open

JU3

Reference designator, not used

JU2

Open

JU1

Open

Rubber feet

None

32.768kHz watch crystal

Maxim MAX707CPA

74HCT245 bidirectional buffer

62256 (32K x 8) static RAM

7805 regulator, TO-220 size

27C256 EPROM containing
monitor program

Maxim MAX233CPP

68HC16 礐
MC68HC16Z1CFC16 (132-pin
plastic quad flat pack)

330k

, 5% resistor

DESCRIPTION

QTY

DESIGNATION

Heatsink for U4, thermalloy # 6078

None

3" x 5" printed circuit board

None

20-pin socket for U6

None

28-pin socket for U3

None

10k

, 5% resistors

R3, R4

_____________________________________________68HC16 Module Component List

Slide switch

SW1

Momentary pushbutton switch

SW2

470

, 5% resistor

10k

SIP resistor

68HC16 Module

________________________________________________________________ Maxim Integrated Products

19-1322; Rev 0; 12/97

For free samples and the latest literature, visit www.maxim-ic.com or phone 1-800-998-8800.
For small orders, phone 1-800-835-8769.

68HC16 Module

_______________________________________________________________________________________

The 68HC16 uses a phase-locked loop (PLL) to set its
bus speed. Crystal Y1 is a 32.768kHz frequency refer-
ence. The internal oscillator runs 256 times faster than the
external crystal. When the 68HC16 is reset, it waits for the
PLL to lock before it executes any software. After the PLL
locks onto the reference frequency, the software doubles
the clock speed by writing to the clock synthesizer con-
trol register, selecting a bus speed of 16.78MHz.

U5, the user RAM area, is a 32kbyte CMOS static RAM.

The 74HCT245 octal buffer lets the 68HC16 module
access an 8-bit port on the 40-pin interface connector.
This memory-mapped port consists of separate read
and write strobes, four chip selects, four address LSBs,
and eight data bits.

Serial Communications

J3 is an RS-232 serial port, designed to be compatible
with the IBM PC 9-pin serial port. Use a straight-
through DB9 male-to-female cable to connect J3 to this
port. If the only available serial port has a 25-pin con-
nector, you may use a standard 25-pin to 9-pin
adapter. Table 1 shows the pinout of J3.

The MAX233 is an RS-232 interface voltage level shifter
with two transmitters and two receivers. It includes a
built-in charge pump with internal capacitors that gener-
ates the output voltages necessary to drive RS-232 lines.

40-Pin Data Connector J1

The 20 x 2 pin header connects the 68HC16 module to
a Maxim EV kit. Table 2 lists the function of each pin.
Note that 68HC16 object code is not compatible with
68HC11 object code. Use the 68HC16 module only
with those modules that are designed to support it, and
only download code that is targeted for the 68HC16
module. Downloading incorrect object code into the
68HC16 module will have unpredictable results.

Address Ranges

The 68HC16 礐 generates various enable signals for dif-
ferent address ranges. The ROM and RAM enable sig-
nals are fed directly to the respective chips. Several
additional signals (J1.11璊1.14) are available on the data
connector to be used by Maxim EV kits. Table 3 outlines
the address ranges for each of the elements found on
the 68HC16 module, and Table 4 is a truth table that
describes the logic for each of the 68HC16's chip-select
outputs. Because the addresses are not completely
decoded, the boot ROM and user RAM have shadows.

Unused

None

Handshake; hard-wired to RTS

CTS

Handshake; hard-wired to CTS

RTS

Handshake; hard-wired to DCD and DTR

DSR

Signal ground connection

GND

Handshake; hard-wired to DCD and DSR

DTR

RS-232-compatible data input to
68HC16 module

TXD

Handshake; hard-wired to DTR and DSR

DCD

FUNCTION

NAME

PIN

RS-232-compatible data output from
68HC16 module

RXD

Table 1. Serial Communications Port J3

Table 2. 40-Pin Data-Connector Signals

General I/O port bit 7

IC4

General I/O port bit 0 (LSB)

IC1

Buffered data bus bits 1�7

EXTD1�7

20�26

Buffered data bus 0 (LSB)

EXTD0

Ground

GND

1�4

FUNCTION

NAME

PIN

Unregulated input voltage

VPREREG

5, 6

Read strobe

+5V from on-board regulator

VCC

7, 8

Chip select for 7E000�7E7FF

7E000

Chip select for 7F000�7F7FF

7F000

Write strobe

Chip select for 7E800�7EFFF

7E800

Address bit 0 (LSB)

A00

Chip select for 7F800�7FFFF

7F800

Pulse-width-modulator output

PWMA

QSPI chip-select output

PCS0/SS

QSPI serial clock

SCK

QSPI master-out, slave-in

MOSI

QSPI master-in, slave-out

MISO

Address bit 1

A01

Address bit 2

A02

Address bit 3

A03

General I/O port bit 1

IC2

General I/O port bit 2

IC3

General I/O port bit 3

OC1

General I/O port bit 4

OC2

General I/O port bit 5

OC3

General I/O port bit 6

OC4

System clock output

CLKOUT

68HC16 Module

_______________________________________________________________________________________

Boot ROM

The boot ROM, U3, is configured as an 8-bit memory
device. Resistor R4 pulls data bit 0 low during system
reset, forcing the 礐 to fetch instructions using only the
upper eight data bits. The boot ROM checks the system
and waits for commands from the host. Refer to the EV
kit manual for specific start-up procedures.

Software

All software is supplied on a disk with the EV kit.
Instructions for operating the software are included in
the EV kit manual. Refer to the EV kit manual for more
information.

68HC16 Module Self Check

To test the 68HC16 module's integrity, connect the
power supply to the power terminals (J2). Do not con-
nect anything to J1 or J3. Slide the power switch SW1
to the "ON" position. The LED will light up, and will flash
within 5 seconds.

If the LED flashes with a 50%-on/50%-off duty cycle, then
it passed its self check. Note that this test does not exer-
cise the RS-232 port or the EV kit 40-pin interface, but it
does confirm that the power supply, microprocessor,
ROM, and RAM passed the self test.

If the LED flashes with a 10%-on/90%-off duty cycle,
then it failed its self check. Most likely, the RAM chip
(U5) is bad.

If the LED remains on and does not flash, then the prob-
lem is either U3 (the EPROM), U1 (the microprocessor),
U4 (the regulator), the MAX707 reset generator, or the
power supply. Use a voltmeter to verify that the power
supplies are good. Check the power-supply input and the
+5V output from the regulator. Use an oscilloscope to see
if the 32.768kHz reference oscillator is running.

Table 3. 68HC16 Module Memory Map
(all address values are in 20-bit hex)

Boot ROM (U3, strobed by CSBOOT)

00000�07FFF

FUNCTION

PIN

Shadow of boot ROM

08000�0FFFF

Shadow of user RAM

18000�1FFFF

User RAM (U5, strobed by CS0 and CS2)

10000�17FFF

Unused

20400�7DFFF

Internal standby RAM; 1kbyte

20000�203FF

Not accessed by the 68HC16

80000璅7FFF

External chip select (J1 pin 11) (CS7)

7E000�7E7FF

External chip select (J1 pin 12) (CS8)

7E800�7EFFF

External chip select (J1 pin 13) (CS9)

7F000�7F7FF

External chip select (J1 pin 14) (CS10)

7F800�7FFFF

Unused

F8000璅F6FF

68HC16's built-in ADC (not used)

FF700璅F73F

Unused

FF740璅F8FF

General-purpose timer module (GPT)

FF900璅F93F

Unused

FF940璅F9FF

System integration module (SIM)

FFA00璅FA7F

Unused

FFA80璅FAFF

Internal standby RAM (SRAM)
control registers

FFB00璅FB07

Unused

FFB08璅FBFF

Queued serial module (QSM)

FFC00璅FDFF

Unused

FFE00璅FFFF

68HC16 Module

_______________________________________________________________________________________

Table 4. 68HC16 Chip-Select Outputs Truth Table

1xxxx read

7E0xx read

1xxxx write

7E8xx read

7E0xx write

0xxxx read

CSBOOT

ADDRESS

RANGE

7F0xx write

7F8xx write

7F8xx read

7F0xx read

7E8xx write

CS0

CS1

CS2

CS5

CS6

CS7

CS8

CS9

CS10

2
3
4
5
6
7
8
9

CS6/IOBUFFER

CS1/RDIO

D08
D09
D10
D11
D12
D13
D14
D15

18
17
16
15
14
13
12
11

EXTD0
EXTD1
EXTD2
EXTD3
EXTD4
EXTD5
EXTD6
EXTD7

C13

0.1

礔

470

LED1

GND

PWMB

VCC

TSTME

BKPT/DSCLK

HALT

BERR

MODCLK

DSACK1

DSACK0

IRQ7

10k

SIP

RESISTOR

GND

RESET

VCC

J4-1

J4-3

J4-5

J4-7

J4-9

J4-2

J4-4

J4-6

J4-8

J4-10

BERR

BKPT/DSCLK

FREEZE

IPIPE1/DSI

IPIPE0/DS0

OE
DIR

A1
A2
A3
A4
A5
A6
A7
A8

B1
B2
B3
B4
B5
B6
B7
B8

74HCT245

J1-1
J1-3
J1-5
J1-7
J1-9
J1-11
J1-13
J1-15
J1-17
J1-19
J1-21
J1-23
J1-25
J1-27
J1-29
J1-31
J1-33
J1-35
J1-37
J1-39

J1-2
J1-4
J1-6
J1-8

J1-10
J1-12
J1-14
J1-16
J1-18
J1-20
J1-22
J1-24
J1-26
J1-28
J1-30
J1-32
J1-34
J1-36
J1-38
J1-40

GND
GND

VPREREG

VCC

CS1/RDIO

CS7/7E000
CS9/7F000

A00
A02

EXTD0
EXTD2
EXTD4
EXTD6

IC1
IC3

OC2
OC4

MISO

SCK

CLKOUT

GND
GND
VPREREG
VCC
CS5/WRIO
CS8/7E800
CS10/7F800
A01
A03
EXTD1
EXTD3
EXTD5
EXTD7
IC2
OC1
OC3
IC4
MOSI
PCSO/SS
PWMA

GROUND

UNREGULATED 7V TO 20V

REGULATED +5V

INTEL COMPATIBLE READ/WRITE STROBES

CHIP SELECTS

LOW ADDRESS BITS

8-BIT BUFFERED BIDIRECTIONAL DATA BUS

8-BIT GENERAL I/O PORT

HIGH-SPEED SERIAL INTERFACE (QSM/QSPI)

Figure 1. 68HC16 Module Schematic

68HC16 Module

_______________________________________________________________________________________

FC2
FC1

VDDE

VSSE

FCO

CSBOOT

DATA0
DATA1
DATA2
DATA3

VSSI

DATA4
DATA5
DATA6
DATA7
DATA8
DATA9

VDDE

VSSE

DATA10
DATA11
DATA12
DATA13
DATA14
DATA15

ADDRO

DSACK0
DSACK1

AVEC

VDDE

A01
A02

VCC

VSSE

A03
A04
A05
A06
A07
A08

VSSI

A09
A10
A11
A12
A13
A14

VCC

VSSE

116
115
114
113
112
111
110
109
108
107
106
105
104
103
102
101
100
99
98
97
96
95
94
93
92
91
90
89
88
87
86
85
84

VRL

ADA6

ADA7

VSTBY

XTAL

VDDSYN

EXTAL

VSSI

VDDI

XFC

VDDE

VSSE

CLKOUT

FREEZE/QUOT

TSTME/TSC

BKPT/DSCLK

IPIPE0/DS0

IPIPE1/DS1

RESET

HALT

BERR

IRQ7

IRQ6

IRQ5

IRQ4

IRQ3

IRQ2

IRQ1

MODCLK

R/W

SIZ1

SIZ0

VSSE

18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50

TXD
ADDR1
ADDR2
VDDE
VSSE
ADDR3
ADDR4
ADDR5
ADDR6
ADDR7
ADDR8
VSSI
ADDR9
ADDR10
ADDR11
ADDR12
ADDR13
ADDR14
ADDR15
ADDR16
ADDR17
ADDR18
VDDE
VSSE
VDDA
VSSA
ADA0
ADA1
ADA2
ADA3
ADA4
ADA5
VRH

RXD

PCS3

PCS2

PCS1

PCS0/SS

SCK

MOSI

MISO

VSSE

VDDE

IC1

IC2

IC3

OC1

OC2

VSSI

VDDI

OC3

OC4

IC4/OC5

PAI

PWMA

PWMB

PCLK

VSSE

VDDE

ADDR23

ADDR22

ADDR21

ADDR20

ADDR19

BGACK

132

131

130

129

128

127

126

125

124

123

122

121

120

119

118

117

CSO/WRRAM
CS5/WRIO

VCC
VSSE

CSBOOT/RDROM
DOO

VSSI

DO8
DO9
VCC
VSSE
D10
D11
D12
D13
D14
D15
AOO
DSACKO
DSACK1

VCC

RXD

TXD

VCC
CS10/7F800
CS9/7F000
CS8/7E800
CS7/7E000
CS6/IOBUFFER
CS2/RDRAM
CS1/RDIO

VSSE

VCC

IC1

IC2

IC3

OC1

OC2

VSSI

VDDI

OC3

OC4

IC4

PWMA

PWMB

VSSE

MISO
MOSI

SCK

PCSO/SS

XTAL

EXTAL

VSSI

VDDI

VCC

VSSE

CLKOUT

FREEZE

TSTME

BKPT/DSCLK

IPIPEO/DS0

IPIPE1/DSI

RESET

HALT

BERR

IRQ7

MODCLK

VSSE

VCC

VSSE

VSTBY

L2
10

礖

OPTIONAL

C3
1

礔

20V

VSSI

C10
0.1

礔

C14
0.1

礔

C8
0.01

礔

MOTOROLA

MC68HC16Z1CFC16

JU4

Figure 1. 68HC16 Module Schematic (continued)

协谢械泻褌褉芯薪薪褘泄 泻芯屑锌芯薪械薪褌: 68HC16

协谢械泻褌褉芯薪薪褘泄泻芯屑锌芯薪械薪褌: 68HC16