Cypress CY7C63513C manual Encoding, What the SIE does to Mode bits PID Status bits Interrupt?

CY7C63413C

CY7C63513C

CY7C63613C

Figure 7. Decode table forTable 29: “Details of Modes for Differing Traffic Conditions”

		Properties of incoming packet
Encoding				Status bits			What the SIE does to Mode bits
					PID Status bits					Interrupt?
End Point									End Point
Mode									Mode
3	1 0	Token	count buffer dval	DTOG DVAL	Set-	In	Out	ACK	3 2	Re-	In
2					COUNT up					1 0 sponse	t

Setup

In

Out

The validity of the received data

The quality status of the DMA buffer

The number of received bytes

Legend:	UC: unchanged	TX: transmit
	x: don’t care	RX: receive

Acknowledge phase completed

TX0: transmit 0-length packet

available for Control endpoint only

The response of the SIE can be summarized as follows:

1.the SIE will only respond to valid transactions, and will ig- nore non-valid ones;

2.the SIE will generate IRQ when a valid transaction is completed or when the DMA buffer is corrupted

3.an incoming Data packet is valid if the count is <= 10 (CRC inclusive) and passes all error checking;

4.a Setup will be ignored by all non-Control endpoints (in appropriate modes);

5.an In will be ignored by an Out configured endpoint and vice versa.

The In and Out PID status is updated at the end of a trans- action.

The Setup PID status is updated at the beginning of the Data packet phase.

The entire EndPoint 0 mode and the Count register are locked to CPU writes at the end of any transaction in which an ACK is transferred. These registers are only unlocked upon a CPU read of these registers, and only if that read happens after the transaction completes. This represents about a 1-∝s window to which to the CPU is locked from register writes to these USB registers. Normally the firmware does a register read at the beginning of the ISR to unlock and get the mode register infor- mation. The interlock on the Mode and Count registers ensures that the firmware recognizes the changes that the SIE might have made during the previous transaction.

Document #: 38-08027 Rev. *B Page 22 of 32

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