Address offset: 0x408
Host Frame Number/Frame Time Remaining Register
This register indicates the current frame number. It also indicates the time remaining (in terms of the number of PHY clocks) in the current (micro)frame. Note: Read the reset value of this register only after the following conditions: - If IDDIG_FILTER is disabled, read only when the PHY clock is stable. - If IDDIG_FILTER is enabled, read only after the filter timer expires.
| Bit number | 31 | 30 | 29 | 28 | 27 | 26 | 25 | 24 | 23 | 22 | 21 | 20 | 19 | 18 | 17 | 16 | 15 | 14 | 13 | 12 | 11 | 10 | 9 | 8 | 7 | 6 | 5 | 4 | 3 | 2 | 1 | 0 | |||
|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
| ID | B | B | B | B | B | B | B | B | B | B | B | B | B | B | B | B | A | A | A | A | A | A | A | A | A | A | A | A | A | A | A | A | |||
| Reset 0x00003FFF | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 1 | 1 | 1 | 1 | 1 | 1 | 1 | 1 | 1 | 1 | 1 | 1 | 1 | 1 | |||
| ID | R/W | Field | Value ID | Value | Description | ||||||||||||||||||||||||||||||
| A |
R |
FRNUM |
Frame Number (FrNum) This field increments when a new SOF is transmitted on the USB, and is reset to 0 when it reaches 16'h3FFF. |
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|
INACTIVE |
0 |
No SOF is transmitted |
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|
ACTIVE |
1 |
SOF is transmitted |
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| B |
R |
FRREM |
Frame Time Remaining (FrRem) Indicates the amount of time remaining in the current microframe (HS) or Frame (FS/LS), in terms of PHY clocks. This field decrements on each PHY clock. When it reaches zero, this field is reloaded with the value in the Frame Interval register and a new SOF is transmitted on the USB. |
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