Cypress CY7C68033 manual Default High-Speed Alternate Settings2, External Fifo Interface, Gpif

							CY7C68033/CY7C68034
Table 6. Default Full-Speed Alternate Settings[2, 3] (continued)
ep4		0		64 bulk out (2×)		64 bulk out (2×)			64 bulk out (2×)
ep6		0		64 bulk in (2×)		64 int in (2×)			64 iso in (2×)
ep8		0		64 bulk in (2×)		64 bulk in (2×)			64 bulk in (2×)
Default High-Speed Alternate Settings
Table 7. Default High-Speed Alternate Settings[2, 3]
Alternate Setting	0		1		2			3
ep0	64		64		64			64
ep1out	0		512 bulk[4]		64 int			64 int
ep1in	0		512 bulk[4]		64 int			64 int
ep2	0		512 bulk out (2×)		512 int out (2×)			512 iso out (2×)
ep4	0		512 bulk out (2×)		512 bulk out (2×)			512 bulk out (2×)
ep6	0		512 bulk in (2×)		512 int in (2×)			512 iso in (2×)
ep8	0		512 bulk in (2×)		512 bulk in (2×)			512 bulk in (2×)

External FIFO Interface

Architecture

The NX2LP-Flex slave FIFO architecture has eight 512-byte blocks in the endpoint RAM that directly serve as FIFO memories, and are controlled by FIFO control signals (such as SLCS#, SLRD, SLWR, SLOE, PKTEND, and flags).

In operation, some of the eight RAM blocks fill or empty from the SIE, while the others are connected to the I/O transfer logic. The transfer logic takes two forms, the GPIF for internally generated control signals, or the slave FIFO interface for externally controlled transfers.

Master/Slave Control Signals

The NX2LP-Flex endpoint FIFOS are implemented as eight physically distinct 256x16 RAM blocks. The 8051/SIE can switch any of the RAM blocks between two domains, the USB (SIE) domain and the 8051-I/O Unit domain. This switching is done virtually instantaneously, giving essentially zero transfer time between ‘USB FIFOS’ and ‘Slave FIFOS.’ Since they are physically the same memory, no bytes are actually transferred between buffers.

At any given time, some RAM blocks are filling/emptying with USB data under SIE control, while other RAM blocks are available to the 8051 and/or the I/O control unit. The RAM blocks operate as single-port in the USB domain, and dual-port in the 8051-I/O domain. The blocks can be configured as single, double, triple, or quad buffered as previ- ously shown.

The I/O control unit implements either an internal-master (M for master) or external-master (S for Slave) interface.

In Master (M) mode, the GPIF internally controls FIFOADR[1:0] to select a FIFO. The two RDY pins can be used as flag inputs from an external FIFO or other logic if desired. The GPIF can be run from an internally derived clock

Note

(IFCLK), at a rate that transfers data up to 96 Megabytes/s (48-MHz IFCLK with 16-bit interface).

In Slave (S) mode, the NX2LP-Flex accepts an internally derived clock (IFCLK, max. frequency 48 MHz) and SLCS#, SLRD, SLWR, SLOE, PKTEND signals from external logic. Each endpoint can individually be selected for byte or word operation by an internal configuration bit, and a Slave FIFO Output Enable signal SLOE enables data of the selected width. External logic must ensure that the output enable signal is inactive when writing data to a slave FIFO. The slave interface must operate asynchronously, where the SLRD and SLWR signals act directly as strobes, rather than a clock qualifier as in a synchronous mode. The signals SLRD, SLWR, SLOE and PKTEND are gated by the signal SLCS#.

GPIF and FIFO Clock Rates

An 8051 register bit selects one of two frequencies for the internally supplied interface clock: 30 MHz and 48 MHz. A bit within the IFCONFIG register will invert the IFCLK signal.

The default NAND firmware image implements a 48-MHz internally supplied interface clock. The NAND boot logic uses the same configuration to implement 100-ns timing on the NAND bus to support proper detection of all NAND Flash types.

GPIF

The GPIF is a flexible 8- or 16-bit parallel interface driven by a user-programmable finite state machine. It allows the NX2LP-Flex to perform local bus mastering, and can implement a wide variety of protocols such as 8-bit NAND interface, printer parallel port, and Utopia. The default NAND firmware and boot logic utilizes GPIF functionality to interface with NAND Flash.

The GPIF on the NX2LP-Flex features three programmable control outputs (CTL) and two general-purpose ready inputs (RDY). The GPIF data bus width can be 8 or 16 bits. Because

4. Even though these buffers are 64 bytes, they are reported as 512 for USB 2.0 compliance. The user must never transfer packets larger than 64 bytes to EP1.

Document #: 001-04247 Rev. *D Page 10 of 33

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