Programming Model

NOTE

In order to keep the chip selects asserted for all transfers, the QWR[CSIV] bit must be set to control the level that the chip selects return to after the first transfer.

QSPICS[3:0]

QS1

QSPI_CLK

 

 

 

 

 

 

 

QS2

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

QSPI_DOUT

 

 

 

 

 

 

 

 

 

 

 

QS3

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

QSPI_DIN

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

Min

QS1: QSPICS to QSPI_CLK

1T1

QS2: QSPI_CLK to QSPI_DOUT VALID

 

 

QS3: QSPI_CLK to QSPI_DOUT HOLD

0 ns

QS4: QSPI_DIN to QSPI_CLK SETUP

10 ns

QS5: QSPI_DIN to QSPI_CLK HOLD

10 ns

1 T1 is defined as the clock period in ns.

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

QS4

 

QS5

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

Max

20 ns

Figure 22-11. QSPI Timing

22.5.8 Programming Example

The following steps are necessary to set up the QSPI 12-bit data transfers and a QSPI_CLK of 4.125 MHz. The QSPI RAM is set up for a queue of 16 transfers. All four QSPI_CS signals are used in this example.

1.Write the QMR with 0xB308 to set up 12-bit data words with the data shifted on the falling clock edge, and a QSPI_CLK frequency of 4.125 MHz (assuming a 66-MHz system clock).

2.Write QDLYR with the desired delays.

22-16

MCF5282 User’s Manual

MOTOROLA

Page 472
Image 472
Motorola MCF5282, MCF5281 user manual Programming Example, QSPICS30, Qspiclk QS2 Qspidout QS3 Qspidin, QS4 QS5