Texas Instruments TMS320DM357 User Manual
4.68 NAKLimit0 Register (Host mode only) (HOST_NAKLIMIT0)
4.69 Transmit Interval Register (Host mode only) (HOST_TXINTERVAL)
Registers
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The NAKLimit0 Register (Host mode only) (HOST_NAKLIMIT0) is shown in
and described in
.
Figure 83. NAKLimit0 Register (Host mode only) (HOST_NAKLIMIT0)
7
5
4
0
Reserved
EP0NAKLIMIT
R-0
R/W-0
LEGEND: R/W = Read/Write; R = Read only; -n = value after reset
Table 84. NAKLimit0 Register (Host mode only) (HOST_NAKLIMIT0) Field Descriptions
Bit
Field
Value
Description
7-5
Reserved
0
Reserved
4-0
EP0NAKLIMIT
0-1Fh
Sets the number of frames/microframes (high-speed transfers) after which Endpoint 0 should time
out on receiving a stream of NAK responses. The number of frames/microframes selected is 2
out on receiving a stream of NAK responses. The number of frames/microframes selected is 2
(—1)
(where m is the value set in the register, valid values 2-16). If the host receives NAK responses
from the target for more frames than the number represented by the Limit set in this register, the
endpoint will be halted.
from the target for more frames than the number represented by the Limit set in this register, the
endpoint will be halted.
Note: A value of 0 or 1 disables the NAK timeout function.
The Transmit Interval Register (Host mode only) (HOST_TXINTERVAL) is shown in
and
described in
.
Figure 84. Transmit Interval Register (Host mode only) (HOST_TXINTERVAL)
7
0
POLINTVL_NAKLIMIT
R/W-0
LEGEND: R/W = Read/Write; -n = value after reset
Table 85. Transmit Interval Register (Host mode only) (HOST_TXINTERVAL) Field Descriptions
Bit
Field
Value
Description
7-0
POLINTVL_NAKLIMIT
0-FFh
For Interrupt and Isochronous transfers, defines the polling interval for the
currently-selected transmit endpoint. For Bulk endpoints, this register sets the number of
frames/microframes after which the endpoint should timeout on receiving a stream of NAK
responses There is a transmit Interval register for each configured transmit endpoint
(except Endpoint 0). In each case the value that is set defines a number of
frames/microframes (High Speed transfers), as follows:
currently-selected transmit endpoint. For Bulk endpoints, this register sets the number of
frames/microframes after which the endpoint should timeout on receiving a stream of NAK
responses There is a transmit Interval register for each configured transmit endpoint
(except Endpoint 0). In each case the value that is set defines a number of
frames/microframes (High Speed transfers), as follows:
Transfer Type Speed Valid values (m) Interpretation
Interrupt Low Speed or Full Speed 1 - 255 Polling interval is m frames
High Speed 1 - 16 Polling interval is 2
(—1)
microframes
Isochronous Full Speed or High Speed 1 - 16 Polling interval is 2
(—1)
frames/microframes
Bulk Full Speed or High Speed 2 - 16 NAK Limit is 2
(—1)
frames/microframes
Note: A value of 0 or 1 disables the NAK timeout function.
130
Universal Serial Bus (USB) Controller
SPRUGH3 – November 2008