MC68MH360EM33L Freescale Semiconductor, MC68MH360EM33L Datasheet - Page 334

• Manufacturer Part Number: MC68MH360EM33L
• Description: IC MPU QUICC ETHER 33MHZ 240FQFP
• Manufacturer: Freescale Semiconductor

Specifications of MC68MH360EM33L

• Processor Type: M683xx 32-Bit
• Speed: 33MHz
• Voltage: 5V
• Mounting Type: Surface Mount
• Package / Case: 240-FQFP
• Lead Free Status / RoHS Status: Contains lead / RoHS non-compliant
• Features: -

Dual-Port RAM
Only the parameters in the parameter RAM and the microcode RAM option require fixed
addresses to be used. The buffer descriptors, buffer data, and scratchpad RAM may be
located in the internal system RAM or in any unused parameter RAM (for instance, in the
available area when a serial channel or sub-block is not being used).
When a microcode from RAM is executed, certain portions of the system RAM are no longer
available. This includes either the first 512-byte block and the last 256-byte block for a small
RAM microcode, and the first two 512-byte blocks and the last 256-byte block for a large
RAM microcode. The third 512-byte block is always available as system RAM.
7.3.1 Buffer Descriptors
The SCCs, SMCs, SPI always use buffer descriptors for controlling data buffers. The buffer
descriptor format of the SCCs, SMCs, and SPI is identical. The buffer descriptor format for
these channels is shown in the following illustration.
If the IDMA is used in the buffer chaining or auto buffer mode, the IDMA channel also uses
buffer descriptors. The buffer descriptors for the IDMA are described in 7.6.1 IDMA Key Fea-
tures;.
7.3.2 Parameter RAM
The CP maintains a section of dual-port RAM called the parameter RAM. This RAM contains
many parameters for the operation of the SCCs, SMCs, SPI, and the IDMA channels. An
overview of the parameter RAM structure is shown in Figure 7-4. The exact definition of the
parameter RAM is contained in each subsection describing a device that uses a parameter
RAM.
7-10
OFFSET + 0
OFFSET + 2
OFFSET + 4
OFFSET + 6
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HIGH-ORDER DATA BUFFER POINTER
LOW-ORDER DATA BUFFER POINTER
STATUS AND CONTROL
DATA LENGTH
150
MOTOROLA