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
SGUS062A–JUNE 2009 –REVISED APRIL 2010
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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 tsu(DRV-CKXH) Setup time, DR valid before CLKX high P– 10 8P – 10 ns
M40 th(CKXH-DRV) Hold time, DR valid after CLKX high P – 10 8P– 10 ns
M41 tsu(FXL-CKXH) Setup time, FSX low before CLKX high 16P + 10 ns
M42 tc(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 th(CKXL-FXL) Hold time, FSX low after CLKX low P ns
M35 td(FXL-CKXH) Delay time, FSX low to CLKX high 2P ns
Disable time, DX high impedance following last data bit
M37 tdis(CKXL-DXHZ) P + 6 7P + 6 ns
from CLKX low
M38 td(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
146 Electrical Specifications Copyright © 2009–2010, Texas Instruments Incorporated
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