MC68376BGMAB20 Freescale Semiconductor, MC68376BGMAB20 Datasheet - Page 100

• Manufacturer Part Number: MC68376BGMAB20
• Description: IC MCU 32BIT 8K ROM 160-QFP
• Manufacturer: Freescale Semiconductor
• Series: M683xxr

Specifications of MC68376BGMAB20

• Core Processor: CPU32
• Core Size: 32-Bit
• Speed: 20MHz
• Connectivity: CAN, EBI/EMI, SCI, SPI
• Peripherals: POR, PWM, WDT
• Number Of I /o: 18
• Program Memory Type: ROMless
• Ram Size: 7.5K x 8
• Voltage - Supply (vcc/vdd): 4.75 V ~ 5.25 V
• Data Converters: A/D 16x10b
• Oscillator Type: External
• Operating Temperature: -40°C ~ 125°C
• Package / Case: 160-QFP
• Lead Free Status / RoHS Status: Lead free / RoHS Compliant
• Eeprom Size: -
• Program Memory Size: -

5.5.1.4 Data Strobe
5.5.1.5 Read/Write Signal
5.5.1.6 Size Signals
5.5.1.7 Function Codes
5-22
MOTOROLA
Data strobe (DS) is a timing signal. For a read cycle, the MCU asserts DS to signal an
external device to place data on the bus. DS is asserted at the same time as AS during
a read cycle. For a write cycle, DS signals an external device that data on the bus is
valid. The MCU asserts DS one full clock cycle after the assertion of AS during a write
cycle.
The read/write signal (R/W) determines the direction of the transfer during a bus cycle.
This signal changes state, when required, at the beginning of a bus cycle, and is valid
while AS is asserted. R/W only transitions when a write cycle is preceded by a read
cycle or vice versa. The signal may remain low for two consecutive write cycles.
Size signals (SIZ[1:0]) indicate the number of bytes remaining to be transferred during
an operand cycle. They are valid while the AS is asserted. Table 5-9 shows SIZ0 and
SIZ1 encoding.
The CPU generates function code signals (FC[2:0]) to indicate the type of activity oc-
curring on the data or address bus. These signals can be considered address exten-
sions that can be externally decoded to determine which of eight external address
spaces is accessed during a bus cycle.
Address space 7 is designated CPU space. CPU space is used for control information
not normally associated with read or write bus cycles. Function codes are valid while
AS is asserted.
Table 5-10 shows address space encoding.
Table 5-9 Size Signal Encoding
SIZ1
0
1
1
0
SYSTEM INTEGRATION MODULE
SIZ0
1
0
1
0
Transfer Size
Three bytes
Long word
Word
Byte
USER’S MANUAL
MC68336/376