MC68MH360EM25L Freescale Semiconductor, MC68MH360EM25L Datasheet - Page 648

• 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: -

Serial Peripheral Interface (SPI)
7.12.5.4.3 INIT RX PARAMETERS Command. This command initializes all the receive
parameters in this serial channel’s parameter RAM to their reset state. This command
should only be issued when the receiver is disabled. Note that the INIT TX AND RX PARAM-
ETERS command may also be used to reset both receive and transmit parameters.
7.12.5.5 SPI BUFFER DESCRIPTOR RING. The data associated with the SPI is stored in
buffers, which are referenced by BDs organized in a BD ring located in the dual-port RAM
(see Figure 7-83). This ring has the same basic configuration as those used by the SCCs
and SMCs.
The BD ring allows the user to define buffers for transmission and buffers for reception. Each
BD ring forms a circular queue. The CP confirms reception and transmission or indicates
error conditions using the BDs to inform the processor that the buffers have been serviced.
The actual buffers may reside in either external memory or internal memory. Data buffers
may reside in the parameter area of an SCC if it is not enabled.
7.12.5.5.1 SPI Receive Buffer Descriptor (Rx BD). The CP reports information about
each buffer of received data using Rx BDs. The CP closes the current buffer, generates a
maskable interrupt, and starts receiving data in the next buffer when the current buffer is full.
Additionally, it will close the buffer when the SPI is configured as a slave and the SPISEL
pin goes to an inactive state, indicating that the reception process is terminated.
The first word of the Rx BD contains status and control bits. These bits are prepared by the
user before reception and are set by the CP after the buffer has been closed. The second
word contains the data length, in bytes, that was received. The third and fourth words con-
tain a pointer that always points to the beginning of the received data buffer.
7-324
POINTER TO SPI
POINTER TO SPI
DUAL-PORT RAM
TX DATA BUFFER
TX RING
RX RING
Freescale Semiconductor, Inc.
Figure 7-83. SPI Memory Structure
For More Information On This Product,
MC68360 USER’S MANUAL
Go to: www.freescale.com
FRAME STATUS
FRAME STATUS
DATA POINTER
DATA POINTER
DATA LENGTH
DATA LENGTH
TX BD RING
RX BD RING
EXTERNAL MEMORY
TX DATA BUFFER
RX DATA BUFFER
MOTOROLA