MC68MH360EM25L Freescale Semiconductor, MC68MH360EM25L Datasheet - Page 333

• Manufacturer Part Number: MC68MH360EM25L
• Description: IC MPU QUICC ETHER 25MHZ 240FQFP
• Manufacturer: Freescale Semiconductor

Specifications of MC68MH360EM25L

• Processor Type: M683xx 32-Bit
• Speed: 25MHz
• Voltage: 5V
• Mounting Type: Surface Mount
• Package / Case: 240-FQFP
• Lead Free Status / RoHS Status: Contains lead / RoHS non-compliant
• Features: -

The dual-port RAM can be accessed by the RISC or one of four bus masters: CPU32+ core,
IDMAs, SDMAs, or external bus master. When the dual-port RAM is accessed by an exter-
nal bus master, CPU32+ core, IDMA, or SDMA channel, it is accessed in three clocks. When
the dual-port RAM is accessed by the RISC, it is accessed in one clock. In the case of simul-
taneous access (with at least one write operation), the RISC is delayed by one clock.
When the dual-port RAM is accessed by the CPU32+ core, IDMAs, SDMAs, or external bus
master, the data and address are taken from the IMB. The data is then presented on the IMB
data bus. The RISC has access to the entire dual-port RAM for data fetches and portions of
the system RAM for microcode instruction fetches.
The dual-port RAM is used for five possible tasks; any two tasks can occur simultaneously.
The first use is to store parameters associated with the SCCs, SMCs, SPI, and IDMAs in the
768-byte parameter RAM. The second use is to store the buffer descriptors that describe
where data is to be received and transmitted from. The third use is to store data from the
serial channels. This usage is optional since data may also be stored externally in the sys-
tem memory. The fourth use is to store RAM microcode for the RISC processor. This feature
allows additional protocols to be added by Motorola in the future. The fifth use is for addi-
tional scratchpad RAM space for the user program.
MOTOROLA
PERIPHERAL
CP MICROCODE
INTERNAL
ADDRESS
ADDRESS
ADDRESS
BUS
IMB
Figure 7-3. Dual-Port RAM Block Diagram
Freescale Semiconductor, Inc.
For More Information On This Product,
MC68360 USER’S MANUAL
Go to: www.freescale.com
1792 BYTES
PARMETER
768 BYTES
SYSTEM
BYTES
BYTES
BYTES
BYTES
RAM
RAM
512
512
512
256
CP MICROCODE DATA
PERIPHERAL
DATA BUS
DATA BUS
IMB
Dual-Port RAM
7-9