Texas Instruments TMS320DM357 manual NAKLimit0 Register Host mode only HOSTNAKLIMIT0, EP0NAKLIMIT

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4.68 NAKLimit0 Register (Host mode only) (HOST_NAKLIMIT0)

The NAKLimit0 Register (Host mode only) (HOST_NAKLIMIT0) is shown in Figure 83 and described in Table 84.

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(—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.

Note: A value of 0 or 1 disables the NAK timeout function.

4.69 Transmit Interval Register (Host mode only) (HOST_TXINTERVAL)

The Transmit Interval Register (Host mode only) (HOST_TXINTERVAL) is shown in Figure 84 and described in Table 85.

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:
			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

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