Motorola MPC8260 - Manual (Page 555)

18-31 MPC8260 PowerQUICC II UserÕs Manual MOTOROLA
Part IV. Communications Processor Module
DCM[ERM] = 1 Transfers from peripheral are initiated by DREQ.
DCM[DT] = 1 Assertion of DONE by the peripheral terminates the transfer, interrupt EDN is set to the core,
Current BD is closed and the next BD if valid is opened. Additional DREQ assertions cause the
new BD to be transferred.
DCM[S/D] = 01 Memory-to-peripheral mode. DONE, DREQ, and DACK are connected to the peripheral.
DCM[SINC] = 1. The memory address is incremented after every transfer.
DCM[DINC] = 1 The memory address is incremented after every transfer.
DPR_BUF The IDMA transfer buffer is not used.
IBASE = IBDPTR =
0x0030 The current BD pointer is set to the BD table base address (aligned 16 -bits[3Ð0]=0000).
STS = 0x0004 Transfers from memory to peripheral are always 4 bytes long (60x singles).
DTS = 0x0004 Transfers from memory to peripheral are always 4 bytes long (60x singles).
Every BD[SDTB] = 1 Memory and peripheral are on the 60x bus.
Every BD[DDTB] = 1 Memory and peripheral are on the 60x bus.
Last BD[SDN] = 1 DONE is asserted on the last transfer.
Last BD[DDN] = 1 DONE is asserted on the last transfer.
IDMR3 = 0x0400_0000 The IDMA3 mask register is programmed to enable the IDSR[OB] interrupt only.
SIMR_L = 0x0000_0100 The interrupt controller is programmed to enable interrupts from IDMA3.
PDIRA = 0x2000_0000
PPARA = 0xE000_0000
PSORA = 0xE000_0000
PODRA = 0x4000_0000 Parallel I/O registers are programmed to enable:PA[0] = DREQ3; PA[2] = DACK3; PA[1] =
DONE3.
The peripheral signals are to be connected to these lines accordingly.
RCCR = 0x0000_0080 IDMA3 conÞguration: DREQ is level high. DONE is high to low. request priority is higher than
the SCCs.
89FE = 0x0300 IDMA3_BASE points to 0x0300 where the parameter table base address is located for IDMA3.
CPCR = 0x26C1_0009 START _ IDMA command. IDMA3 page-01001 SBC-10110 op-1001 FLG=1.This write starts the
channel operation.
DMA operation description:
START _ IDMA : Initialize all parameter RAM values, wait for DREQ to open the Þrst BD.
Steady state: Every DREQ triggers a 4-byte transfer in single address transaction. DMA performs a memory read
transaction combined with DACK assertion. Memory address is incremented constantly. Last transaction of the last BD is
combined with DONE assertion.Another DREQ assertion after last BD complete will issue IDSR[OB] interrupt to the core.
STOP _ IDMA : BD is closed. SC bit is set in IDSR (SC interrupt to the core is not enabled).Channel is stopped until
START _ IDMA command is issued.
DONE assertion by the peripheral: current BD is closed. IDSR[EDN] is set (but the interrupt to the core is not
enabled).The next BD is open with the next DREQ assertion (or IDSR[OB] interrupt is set to the core if there is no other
valid BDs).
Table 18-16. Example: Memory-to-Peripheral Fly-By Mode (on 60x)ÐIDMA3 (Continued)
Important Init Values Description