SMJ320C6414 Datasheet, PDF (120/133 Pages) Texas Instruments – FIXED-POINT DIGITAL SIGNAL PROCESSORS

SMJ320C6414, SMJ320C6415, SMJ320C6416
FIXEDĆPOINT DIGITAL SIGNAL PROCESSORS
SGUS050A − JANUARY 2004 − REVISED MARCH 2004
switching characteristics over recommended operating conditions for McBSP as SPI Master or
Slave: CLKSTP = 10b, CLKXP = 0^†‡ (see Figure 53)
NO.
PARAMETER
1 th(CKXL-FXL)
2 td(FXL-CKXH)
Hold time, FSX low after CLKX low¶
Delay time, FSX low to CLKX high#
3 td(CKXH-DXV) Delay time, CLKX high to DX valid
Disable time, DX high impedance following last data bit
6 tdis(CKXL-DXHZ) _{from CLKX low}
MASTER§
SLAVE
MIN MAX
MIN
MAX
T−2 T+3
L − 2* L + 3*
−2
4 12P + 2.8 20P + 17
UNIT
ns
ns
ns
L − 2* L + 3*
ns
7
tdis(FXH-DXHZ)
Disable time, DX high impedance following last data bit
from FSX high
4P + 3* 12P + 17* ns
8 td(FXL-DXV)
Delay time, FSX low to DX valid
8P + 1.8 16P + 17 ns
*This parameter is not production tested.
† _{P = 1/CPU clock frequency in ns. For example, when running parts at 600 MHz, use P = 1.67 ns.}
‡ _{For all SPI Slave modes, CLKG is programmed as 1/4 of the CPU clock by setting CLKSM = CLKGDV = 1.}
§ _{S = Sample rate generator input clock = 4P 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).
CLKX
FSX
DX
1
7
6
Bit 0
DR
Bit 0
2
8
4
Bit(n-1)
Bit(n-1)
3
(n-2)
5
(n-2)
(n-3)
(n-4)
(n-3)
(n-4)
Figure 53. McBSP Timing as SPI Master or Slave: CLKSTP = 10b, CLKXP = 0
120
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