19.4.1 Bus Matrix Host Configuration Registers
This register can only be written if the WPEN bit is cleared in the Write Protection Mode Register.
Name: | MATRIX_MCFGx |
Offset: | 0x00 + x*0x04 [x=0..12] |
Reset: | 0x00000004 |
Property: | Read/Write |
Bit | 31 | 30 | 29 | 28 | 27 | 26 | 25 | 24 | |
Access | |||||||||
Reset |
Bit | 23 | 22 | 21 | 20 | 19 | 18 | 17 | 16 | |
Access | |||||||||
Reset |
Bit | 15 | 14 | 13 | 12 | 11 | 10 | 9 | 8 | |
Access | |||||||||
Reset |
Bit | 7 | 6 | 5 | 4 | 3 | 2 | 1 | 0 | |
ULBT[2:0] | |||||||||
Access | R/W | R/W | R/W | ||||||
Reset | 1 | 0 | 0 |
Bits 2:0 – ULBT[2:0] Undefined Length Burst Type
Value | Name | Description |
---|---|---|
0 | UNLTD_LENGTH | Unlimited Length Burst—No predicted end of burst is generated, therefore INCR bursts coming from this Host can only be broken if the Client Slot Cycle Limit is reached. If the Slot Cycle Limit is not reached, the burst is normally completed by the Host, at the latest, on the next AHB 1-Kbyte address boundary, allowing up to 256-beat word bursts or 128-beat double-word bursts. This value should not be used in the very particular case of a Host capable of performing back-to-back undefined length bursts on a single Client, since this could indefinitely freeze the Client arbitration and thus prevent another Host from accessing this Client. |
1 | SINGLE_ACCESS | Single Access—The undefined length burst is treated as a succession of single accesses, allowing re-arbitration at each beat of the INCR burst or bursts sequence. |
2 | 4BEAT_BURST | 4-beat Burst—The undefined length burst or bursts sequence is split into 4-beat bursts or less, allowing re-arbitration every 4 beats. |
3 | 8BEAT_BURST | 8-beat Burst—The undefined length burst or bursts sequence is split into 8-beat bursts or less, allowing re-arbitration every 8 beats. |
4 | 16BEAT_BURST | 16-beat Burst—The undefined length burst or bursts sequence is split into 16-beat bursts or less, allowing re-arbitration every 16 beats. |
5 | 32BEAT_BURST | 32-beat Burst —The undefined length burst or bursts sequence is split into 32-beat bursts or less, allowing re-arbitration every 32 beats. |
6 | 64BEAT_BURST | 64-beat Burst—The undefined length burst or bursts sequence is split into 64-beat bursts or less, allowing re-arbitration every 64 beats. |
7 | 128BEAT_BURST | 128-beat Burst—The undefined length burst or bursts sequence is split into 128-beat bursts or less, allowing re-arbitration every 128 beats. Note: Unless duly needed, the ULBT should be left at its default 0 value for
power saving.
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