mc68hc916y3 Freescale Semiconductor, Inc, mc68hc916y3 Datasheet - Page 155

• Manufacturer Part Number: mc68hc916y3
• Description: Mc68hc16y3 16 Bit Microcontroller
• Manufacturer: Freescale Semiconductor, Inc

5.7.3.4 8-Bit Expanded Mode
MC68HC16Y3/916Y3
USER’S MANUAL
The SCIM2 uses an 8-bit data bus when BERR = 1 and DATA1 = 1 during reset. In
this configuration, pins DATA[7:0] are configured as port H, an 8-bit I/O port. Pins
DATA[15:8] are configured as data bus pins, and ADDR[18:3] are configured as
address bus pins. The alternate functions for these address and data bus pins as ports
A, B, and G are unavailable. ADDR[23:19]/CS[10:6] are configured as chip selects.
ADDR[2:0] are configured as address bus pins. Emulator mode is always disabled.
DATA8 determines the function of the DSACK[1:0], DS, AS, and SIZ[1:0] pins. If
DATA8 is held low during reset, these pins are used for discrete I/O (port E).
DATA9 determines the function of interrupt request pins (IRQ[7:1]) and the clock mode
select pin (MODCLK). When DATA9 is held low during reset, these pins are used for
discrete I/O (port F).
Table 5-18 summarizes pin function selections for 8-bit data bus operation.
NOTES:
ADDR23/CS10/ECLK
1. These pins have only one reset configuration in 8-bit expanded mode.
ADDR19/CS6/PC3
ADDR20/CS7/PC4
ADDR21/CS8/PC5
ADDR22/CS9/PC6
IRQ[7:1]/PF[7:1]
Pin(s) Affected
FASTREF/PF0
FC0/CS3/PC0
FC2/CS5/PC2
DSACK0/PE0
DSACK1/PE1
BGACK/CSE
CSBOOT
SIZ0/PE6
SIZ1/PE7
FC1/PC1
BG/CSM
BR/CS0
DS/PE4
AS/PE5
Table 5-18 8-Bit Expanded Mode Reset Configuration
Freescale Semiconductor, Inc.
For More Information On This Product,
Select Pin
DATA8
DATA9
N/A
N/A
N/A
N/A
Go to: www.freescale.com
1
1
1
1
Default Function
(Pin Held High)
CSBOOT 8-Bit
FASTREF
DSACK0
DSACK1
CS[10:6]
IRQ[7:1]
BGACK
SIZ0
SIZ1
CS0
CS3
FC1
CS5
DS
AS
BG
Alternate Function
(Pin Held Low)
CSBOOT 8-Bit
CS[10:6]
BGACK
PF[7:1]
FC0
FC1
FC2
PE0
PE1
PE4
PE5
PE6
PE7
PF0
BR
BG
MOTOROLA
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