TMS320C6414T, TMS320C6415T, TMS320C6416T
FIXEDPOINT DIGITAL SIGNAL PROCESSORS
SPRS226M NOVEMBER 2003 REVISED APRIL 2009
123
POST OFFICE BOX 1443
HOUSTON, TEXAS 772511443
MULTICHANNEL BUFFERED SERIAL PORT (McBSP) TIMING (CONTINUED)
timing requirements for McBSP as SPI Master or Slave: CLKSTP = 11b, CLKXP = 0 (see Figure 54)
NO.
600, 720
850, 1G
UNIT
NO.
MASTER
SLAVE
UNIT
MIN
MAX
MIN
MAX
4
tsu(DRV-CKXH) Setup time, DR valid before CLKX high
12
2 12P
ns
5
th(CKXH-DRV)
Hold time, DR valid after CLKX high
4
5 + 24P
ns
P = 1/CPU clock frequency in ns. For example, when running parts at 720 MHz, use P = 1.39 ns.
For all SPI Slave modes, CLKG is programmed as 1/4 of the CPU clock by setting CLKSM = CLKGDV = 1.
switching characteristics over recommended operating conditions for McBSP as SPI Master or
Slave: CLKSTP = 11b, CLKXP = 0 (see Figure 54)
NO.
PARAMETER
600, 720
850, 1G
UNIT
NO.
PARAMETER
MASTER§
SLAVE
UNIT
MIN
MAX
MIN
MAX
1
th(CKXL-FXL)
Hold time, FSX low after CLKX low
L 2
L + 3
ns
2
td(FXL-CKXH)
Delay time, FSX low to CLKX high#
T 2
T + 3
ns
3
td(CKXL-DXV)
Delay time, CLKX low to DX valid
2
4
12P + 2.8
20P + 17
ns
6
tdis(CKXL-DXHZ)
Disable time, DX high impedance following last data bit from
CLKX low
2
4
12P + 3
20P + 17
ns
7
td(FXL-DXV)
Delay time, FSX low to DX valid
H 2
H + 4
8P + 2
16P + 17
ns
P = 1/CPU clock frequency in ns. For example, when running parts at 720 MHz, use P = 1.39 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).
Bit 0
Bit(n-1)
(n-2)
(n-3)
(n-4)
Bit 0
Bit(n-1)
(n-2)
(n-3)
(n-4)
4
3
7
6
2
1
CLKX
FSX
DX
DR
5
Figure 54. McBSP Timing as SPI Master or Slave: CLKSTP = 11b, CLKXP = 0