Datasheet

8−13

SLLS535E − April 2008 TUSB6250

8.9.1 IEPCNFG_0: Input Endpoint-0 Configuration Register (XDATA at F000)

The IEPCNFG_0 register contains various bits used to configure and control this endpoint.

76543210

UBME NAK_INTE TOGLE RSV STALL USBIE BZ

R/W R/W R/O R/O R/W R/W R/W R/W

BIT NAME RESET FUNCTION

1−0 BZ[1:0] 00b Endpoint-0 buffer size for IN and OUT transaction. The value of this field also defines the starting address

of the input buffer. See Table 8−3.

00 = 8 bytes

01 = 16 bytes

10 = 32 bytes

11 = 64 bytes

2 USBIE 0 USB interrupt enable on transaction completion. Set/cleared by the MCU.

USBIE = 0 No interrupt

USBIE = 1 Interrupt on transaction completion

3 STALL 0 USB stall condition indication. Set/cleared by the MCU.

STALL = 0 No stall

STALL = 1 USB stall condition. If set by the MCU, a STALL handshake is initiated and the bit is cleared

automatically by the next setup transaction.

4 RSV 0 Reserved

5 TOGLE 0 USB toggle bit. The hardware resets this bit when the setup packet is received.

6 NAK_INTE 0 NAK interrupt enable

NAK_INTE = 0 NAK does not trigger interrupt.

NAK_INTE = 1 NAK triggers an interrupt.

7 UBME 0 UBM enable/disable bit. Set/cleared by the MCU.

UBME = 0 UBM cannot use this endpoint.

UBME = 1 UBM can use this endpoint.

8.9.2 IEPBCN_0: Input Endpoint-0 Buffer Byte-Count Register (XDATA at F001)

The IEPBCN_0 register contains the NAK bit and the 7-bit value used to specify the amount of data to be

transmitted in a data packet to the USB host.

76543210

NAK C6 C5 C4 C3 C2 C1 C0

R/W R/W R/W R/W R/W R/W R/W R/W

BIT NAME RESET FUNCTION

6−0 C[6:0] 0000000 Byte count. Only count of 0 to 64 (00h to 40h) is supported.

00h Byte count = 0

40h Byte count = 64

41h to 7Fh should not be used. If the MCU writes any value greater than 0x40 to C[6:0], the TUSB6250

hardware corrects it and only writes 0x40 to C[6:0].

7 NAK 1 NAK=0 Buffer contains a valid packet for Host-IN request.

NAK=1 Buffer is empty (TUSB6250 NAKs the host-IN request).