Motorola M68HC11EVB, User Manual

Page: 88 / 103

SUPPORT INFORMATION
M68HC11EVB/D 6-3 3
Table 6-1. MCU I/O Port Connector (P1) Pin Assignments (continued)
Pin Number
Signal
Mnemonic Signal Name and Description
19 IRQ* INTERRUPT REQUEST
–
An active low input line used to
request asynchronous interrupts to the MCU.
20
21
22
23
24
25 PD0
PD1
PD2
PD3
PD4
PD5 PORT D (bits 0-5)
–
General purpose I/O lines. These lines
can be used with the MCU Serial Communications
Interface(SCI) and Serial Peripheral Interface(SPI).
26 VDD VDD
–
+5.0 Vdc power.
27-34 PA7-PA0 PORT A (bits 7-0)
–
General purpose I/O lines.
35-42 PB7-PB0 PORT B (bits 7-0)
–
General purpose output lines.
43
44
45
46
47
48
49
50 PE0
PE4
PE1
PE5
PE2
PE6
PE3
PE7 PORT E (bits 0-7)
–
General purpose input or A/D channel
input lines.
51 VRL VOLTAGE REFERENCE LOW - Input reference supply
voltage (low) line for the MCU analog-to-digital (A/D)
converter. Used to increase accuracy of the A/D conversion.
52 VRH VOLTAGE REFERENCE HIGH - Input reference supply
voltage (high) line. Same purpose as pin 51.
53-60 NC Not connected.