Motorola MVME1X7P manual Programming the VMEchip2 DMA Controller, I2WP, I2EN, ROM Control Register

Models: MVME1X7P

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LCSR Programming Model

 

 

 

 

 

 

 

 

 

 

 

 

 

 

I2WP

 

When this bit is high, write posting is enabled to the local

 

 

 

 

 

bus F page. When this bit is low, write posting is disabled

 

 

 

 

 

to the local bus F page.

 

 

 

 

 

 

I2EN

 

When this bit is high, the F page ($F0000000 through

 

 

 

 

 

$FF7FFFFF) map decoder is enabled. The F0 page is

 

 

 

 

 

defined as A24/D16 on the VMEbus while the F1-FE

 

 

 

 

 

pages are defined as A32/D16. When this bit is low, the F

 

 

 

 

 

page is disabled.

 

 

 

 

ROM Control Register

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

ADR/SIZ

 

 

 

 

 

$FFF4002C

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

BIT

7

 

6

 

5

4

 

3

2

1

0

 

 

 

 

 

 

 

 

 

 

 

 

 

 

NAME

SIZE

 

 

 

BSSPD

 

 

ASPD

 

 

 

 

 

 

 

 

 

 

 

 

 

OPER

R/W

 

 

 

R/W

 

 

R/W

 

 

 

 

 

 

 

 

 

 

 

 

 

RESET

0 PS

 

 

 

0 PS

 

 

0 PS

 

 

 

 

 

 

 

 

 

 

 

 

 

 

This function is not used on the MVME1x7P.

2

Programming the VMEchip2 DMA Controller

This section includes programming information on the DMA controller, VMEbus interrupter, MPU status register, and local-bus-to-VMEbus requester register.

The VMEchip2 features a local-bus -to-VMEbus DMA controller (DMAC). The DMAC has two modes of operation: command chaining, and direct. In direct mode, the local bus address, the VMEbus address, the byte count, and the control register of the DMAC are programmed and the DMAC is enabled. The DMAC transfers data, as programmed, until the byte count is zero or an error is detected. When the DMAC stops, the status bits in the DMAC status register are set and an interrupt is sent to the local bus interrupter. If the DMAC interrupt is enabled in the local bus interrupter, the local bus is interrupted. The time on and time off timers should be programmed to control the VMEbus bandwidth used by the DMAC.

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Page 141
Image 141
Motorola MVME1X7P manual Programming the VMEchip2 DMA Controller, I2WP, I2EN, ROM Control Register