AN413 datasheet(13/45 Pages) STMICROELECTRONICS

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AN413

ST9 basic system configuration

Doc ID 1875 Rev 2

13/45

3.7

SCI unit initialization

The list of registers to be initialized when initializing the SCI unit is given in Table 12. The

functions of these registers, and some illustrative examples of their use, are as follows:

The Receiver DMA Transaction Counter Pointer Register, RDCPR, contains the register file

address of the receiver DMA transaction counter. In addition it determines whether the DMA

transfers occur in the register file or in memory.

Example:

An example of the use of this register is provided below (see RDAPR example).

The Receiver DMA Destination Address Pointer Register, RDAPR, contains the register file

address of the receiver DMA data destination. In addition, in conjunction with bit 0 of

RDCPR, it determines whether the DMA transfers occur in Program or Data memory.

Example:

00 FF LNG-DMA_SCI := 0Fh

00 A0 DEPART_DMA_SCI := 0A0h

00 02 NUM_RDAP := 2

00 03 NUM_RDCP := 3

2C 03 ld S_rdcpr,#NUM_RDCP

1C 02 ld S_rdapr,#NUM_RDAP

F5 03 0F ld R#NUM_RDCP,#(LNG_DMA_SCI)

F5 02 00 ld R#NUM_RDAP,#(DEPART_DMA_SCI)

In this program sequence the DMA transaction counter and Address Pointer register

addresses are defined to be R3 and R2 respectively. These two registers are initialized for a

block of size 15 bytes starting at register address A0, i.e. R160.

The Transmitter DMA Transaction Counter Pointer Register, TDCPR, contains the register

file address of the transmitter DMA transaction counter. In addition it determines whether

the DMA transfers occur in the register file or in memory.

Example:

An example of the use of this register is provided below (see TDAPR example).

The Transmitter DMA Destination Address Pointer Register, TDAPR, contains the register

file address of the transmitter DMA data destination. In addition, in conjunction with bit 0 of

TDCPR, it determines whether the DMA transfers occur in Program or Data memory.

Example:

00 FF LNG-DMA_SCI := 0Fh

00 A0 DEPART_DMA_SCI := 0A0h

00 06 NUM_TDAP := 6

00 07 NUM_TDCP := 7

2C 07 ld S_TDCPR,#NUM_TDCP

3C 06 ld S_TDAPR,#NUM_TDAP

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