Texas Instruments TMS320C6202 - Manual (Page 68)

TMS320C6202
FIXED-POINT DIGITAL SIGNAL PROCESSOR
SPRS072B – AUGUST 1998 – REVISED AUGUST 1999
68
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MULTICHANNEL BUFFERED SERIAL PORT TIMING (CONTINUED)
timing requirements for McBSP as SPI master or slave: CLKSTP = 11b, CLKXP = 1 †‡ (see Figure 45)
NO.
’C6202-200
’C6202-233
’C6202-250
UNIT NO.
MASTER SLAVE
UNIT
MIN MAX MIN MAX
4 tsu(DRV-CKXL) Setup time, DR valid before CLKX low 12 2 – 3P ns
5 th(CKXL-DRV) Hold time, DR valid after CLKX low 4 5 + 6P ns
† P = 1/CPU clock frequency in ns. For example, when running parts at 250 MHz, use P = 4 ns.
‡ For all SPI slave modes, CLKG is programmed as 1/2 of the CPU clock by setting CLKSM = CLKGDV = 1.
switching characteristics for McBSP as SPI master or slave: CLKSTP = 11b, CLKXP = 1 †‡
(see Figure 45)
NO. PARAMETER
’C6202-200
’C6202-233
’C6202-250
UNIT NO. PARAMETER
MASTER§ SLAVE
UNIT
MIN MAX MIN MAX
1 th(CKXH-FXL) Hold time, FSX low after CLKX high¶ H – 2 H + 3 ns
2 td(FXL-CKXL) Delay time, FSX low to CLKX low# T – 2 T + 1 ns
3 td(CKXH-DXV) Delay time, CLKX high to DX valid –2 4 3P + 4 5P + 17 ns
6 tdis(CKXH-DXHZ)
Disable time, DX high impedance following last data bit from
CLKX high
–2 4 3P + 3 5P + 17 ns
7 td(FXL-DXV) Delay time, FSX low to DX valid L – 2 L + 4 2P + 2 4P + 17 ns
† P = 1/CPU clock frequency in ns. For example, when running parts at 250 MHz, use P = 4 ns.
‡ For all SPI slave modes, CLKG is programmed as 1/2 of the CPU clock by setting CLKSM = CLKGDV = 1.
§ S = sample rate generator input clock = P if CLKSM = 1 (P = 1/CPU clock frequency)
= sample rate generator input clock = P_clks if CLKSM = 0 (P_clks = CLKS period)
T = CLKX period = (1 + CLKGDV) * S
H = CLKX high pulse width = (CLKGDV/2 + 1) * S if CLKGDV is even
= (CLKGDV + 1)/2 * S if CLKGDV is odd or zero
L = CLKX low pulse width = (CLKGDV/2) * S if CLKGDV is even
= (CLKGDV + 1)/2 * S if CLKGDV is odd or zero
¶ FSRP = FSXP = 1. As a SPI master, FSX is inverted to provide active-low slave-enable output. As a slave, the active-low signal input on FSX
and FSR is inverted before being used internally.
CLKXM = FSXM = 1, CLKRM = FSRM = 0 for master McBSP
CLKXM = CLKRM = FSXM = FSRM = 0 for slave McBSP
# FSX should be low before the rising edge of clock to enable slave devices and then begin a SPI transfer at the rising edge of the master clock
(CLKX).
Bit 0 Bit(n-1) (n-2) (n-3) (n-4)
Bit 0 Bit(n-1) (n-2) (n-3) (n-4)
5
4
3 7 6
2 1
CLKX
FSX
DX
DR
Figure 45. McBSP Timing as SPI Master or Slave: CLKSTP = 11b, CLKXP = 1
ADV
ANCE INFORMA
TION