Host Controller Data Manual

4–35

4.37 Asynchronous Context Control Register

The asynchronous context control set/clear register controls the state and indicates status of the DMA context. See

Table 4–27 for a complete description of the register contents.

Bit 31 30 29 28 27 26 25 24 23 22 21 20 19 18 17 16

Name Asynchronous context control

Type R R R R R R R R R R R R R R R R

Default 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0

Bit 15 14 13 12 11 10 9 8 7 6 5 4 3 2 1 0

Name Asynchronous context control

Type RSCU R R RSU RU RU R R RU RU RU RU RU RU RU RU

Default 0 0 0 X 0 0 0 0 X X X X X X X X

Type: Read/Set/Clear/Update, Read/Set/Update, Read/Update, Read-only

Offset: 180h set register [ATRQ]

184h clear register [ATRQ]

1A0h set register [ATRS]

1A4h clear register [ATRS]

1C0h set register [ARRQ]

1C4h clear register [ARRQ]

1E0h set register [ARRS]

1E4h clear register [ARRS]

Default: 0000 X0XXh

Table 4–27. Asynchronous Context Control Register Description

BIT FIELD NAME TYPE DESCRIPTION

31–16 RSVD R Reserved. Bits 31–16 return 0s when read.

15 run RSCU

This bit is set by software to enable descriptor processing for the context and cleared by software to

stop descriptor processing. The TSB12LV26 changes this bit only on a hardware or software reset.

14–13 RSVD R Reserved. Bits 14–13 return 0s when read.

12 wake RSU

Software sets this bit to cause the TSB12LV26 to continue or resume descriptor processing. The

TSB12LV26 clears this bit on every descriptor fetch.

11 dead RU

The TSB12LV26 sets this bit when it encounters a fatal error and clears the bit when software resets

bit 15 (run).

10 active RU The TSB12LV26 sets this bit to 1 when it is processing descriptors.

9–8 RSVD R Reserved. Bits 9–8 return 0s when read.

7–5 spd RU

This field indicates the speed at which a packet was received or transmitted, and only contains

meaningful information for receive contexts. This field is encoded as:

000 = 100 Mbits/sec,

001 = 200 Mbits/sec, and

010 = 400 Mbits/sec. All other values are reserved.

4–0 eventcode RU

This field holds the acknowledge sent by the link core for this packet, or holds an internally generated

error code if the packet was not transferred successfully.