MC68376BGMAB20 Freescale Semiconductor, MC68376BGMAB20 Datasheet - Page 99

• 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 Bus Control Signals
5.5.1.1 Address Bus
5.5.1.2 Address Strobe
5.5.1.3 Data Bus
MC68336/376
USER’S MANUAL
The external bus has 24 address lines and 16 data lines. The EBI provides dynamic
sizing between 8-bit and 16-bit data accesses. It supports byte, word, and long-word
transfers. Port width is the maximum number of bits accepted or provided during a bus
transfer. Widths of eight and sixteen bits are accessed through the use of asynchro-
nous cycles controlled by the size (SIZ1 and SIZ0) and data and size acknowledge
(DSACK1 and DSACK0) pins. Multiple bus cycles may be required for dynamically
sized transfers.
To add flexibility and minimize the necessity for external logic, MCU chip-select logic
can be synchronized with EBI transfers. Refer to 5.9 Chip-Selects for more informa-
tion.
The address bus provides addressing information to external devices. The data bus
transfers 8-bit and 16-bit data between the MCU and external devices. Strobe signals,
one for the address bus and another for the data bus, indicate the validity of an ad-
dress and provide timing information for data.
Control signals indicate the beginning of each bus cycle, the address space it is to take
place in, the size of the transfer, and the type of cycle. External devices decode these
signals and respond to transfer data and terminate the bus cycle. The EBI operates in
an asynchronous mode for any port width.
Bus signals ADDR[23:0] define the address of the byte (or the most significant byte)
to be transferred during a bus cycle. The MCU places the address on the bus at the
beginning of a bus cycle. The address is valid while AS is asserted.
Address strobe (AS) is a timing signal that indicates the validity of an address on the
address bus and of many control signals. It is asserted one-half clock after the begin-
ning of a bus cycle.
Signals DATA[15:0] form a bidirectional, non-multiplexed parallel bus that transfers
data to or from the MCU. A read or write operation can transfer eight or sixteen bits of
data in one bus cycle. During a read cycle, the data is latched by the MCU on the last
falling edge of the clock for that bus cycle. For a write cycle, all 16 bits of the data bus
are driven, regardless of the port width or operand size. The MCU places the data on
the data bus one-half clock cycle after AS is asserted in a write cycle.
SYSTEM INTEGRATION MODULE
MOTOROLA
5-21