Texas Instruments Digital Signal Processor SM320F2812-HT User Manual

Page 143

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Bit 0

Bit(n-1)

(n-2)

(n-3)

(n-4)

Bit 0

Bit(n-1)

(n-2)

(n-3)

(n-4)

CLKX

FSX

DX

DR

M35

M37

M40

M39

M38

M34

LSB

MSB

M41

M42

SM320F2812-HT

www.ti.com

SGUS062B

JUNE 2009

REVISED JUNE 2011

Table 6-56. McBSP as SPI Master or Slave Timing Requirements (CLKSTP = 11b, CLKXP = 0)

(1)

MASTER

SLAVE

NO.

UNIT

MIN

MAX

MIN

MAX

M39

t

su(DRV-CKXH)

Setup time, DR valid before CLKX high

P

10

8P

10

ns

M40

t

h(CKXH-DRV)

Hold time, DR valid after CLKX high

P

10

8P

10

ns

M41

t

su(FXL-CKXH)

Setup time, FSX low before CLKX high

16P + 10

ns

M42

t

c(CKX)

Cycle time, CLKX

2P

16P

ns

(1)

Not production tested.

Table 6-57. McBSP as SPI Master or Slave Switching Characteristics (CLKSTP = 11b, CLKXP = 0)

(1) (2)

MASTER

SLAVE

NO.

PARAMETER

UNIT

MIN

MAX

MIN

MAX

M34

t

h(CKXL-FXL)

Hold time, FSX low after CLKX low

P

ns

M35

t

d(FXL-CKXH)

Delay time, FSX low to CLKX high

2P

ns

Disable time, DX high impedance following last data bit

M37

t

dis(CKXL-DXHZ)

P + 6

7P + 6

ns

from CLKX low

M38

t

d(FXL-DXV)

Delay time, FSX low to DX valid

6

4P + 6

ns

(1)

Not production tested.

(2)

2P = 1/CLKG
For all SPI slave modes, CLKX has to be minimum eight CLKG cycles. Also, CLKG should be LSPCLK/2 by setting CLKSM = CLKGDV
= 1. With maximum LSPCLK speed of 75 MHz, CLKX maximum frequency is LSPCLK/16 , that is 4.5 MHz and P = 13.3 ns.

Figure 6-44. McBSP Timing as SPI Master or Slave: CLKSTP = 11b, CLKXP = 0

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©

2009

2011, Texas Instruments Incorporated

Electrical Specifications

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