32.17.2 Host Start-of-Frame Control
Name: | HSOFC |
Offset: | 0x0A |
Reset: | 0x00 |
Property: | PAC Write-Protection |
Bit | 7 | 6 | 5 | 4 | 3 | 2 | 1 | 0 | |
FLENCE | FLENC[3:0] | ||||||||
Access | R/W | R/W | R/W | R/W | R/W | ||||
Reset | 0 | 0 | 0 | 0 | 0 |
Bit 7 – FLENCE Frame Length Control Enable
Note: In Low Speed
mode, FLENCE must be '0'.
FLENCE | Frame Timing | Internal Frame Length Down-Counter Load Value |
---|---|---|
0 | Internal Frame Length (Full Speed) | 11999 (1ms frame rate at 12MHz) |
0 | Internal Frame Length in Low and Full speed | 59999 (1ms frame rate at 60MHz) |
Internal Frame Length in High speed | 7499 (0.125ms micro-frame rate at 60MHz) | |
1 | Beginning of Frame | FLENC[3:0] |
Internal Frame Length with Frame correction | 11999 + FLENC[3:0] at all speeds. |
Value | Description |
---|---|
0 | Start-of-Frame is generated every 1ms. |
1 | Start-of-Frame generation
depends on the signed value of FLENC[3:0]. USB Start-of-Frame period equals 1ms + (FLENC[3:0]/12000)ms |
Bits 3:0 – FLENC[3:0] Frame Length Control
These bits define the signed value of the 4-bit FLENC that is added to the Internal Frame Length when FLENCE is '1'. The internal Frame length is the top value of the frame counter when FLENCE is zero.