
SPRS457E
– MARCH 2009 – REVISED JUNE 2011
Table 6-74. Switching Characteristics Over Recommended Operating Conditions for McBSP(1) (2) (3)
DEVICE
NO.
PARAMETER
UNIT
MIN
MAX
CLKR/X int
2(4) (5) tc(CKRX)
Cycle time, CLKR/X
38.5 or 2P
ns
CLKR/X ext
17
td(CLKS-CLKRX)
Delay time, CLKS high to internal CLKR/X
CLKR/X int
1
24
CLKR/X int
19.25 - 1 or P - 1
3(6)
tw(CKRX)
Pulse duration, CLKR/X high or CLKR/X low
ns
CLKR/X ext
19.25 or P
CLKR int
-4
8
4
td(CKRH-FRV)
Delay time, CLKR high to internal FSR valid
ns
CLKR ext
3
25
CLKX int
-4
8
9
td(CKXH-FXV)
Delay time, CLKX high to internal FSX valid
ns
CLKX ext
3
25
CLKX int
12
ns
tdis(CKXH-
Disable time, DX high impedance following last data
12
DXHZ)
bit from CLKX high
CLKX ext
25
ns
CLKX int
-5 + D1(7)
12 + D2(7)
ns
13
td(CKXH-DXV)
Delay time, CLKX high to DX valid
CLKX ext
3 + D1(7)
25 + D2(7)
ns
Delay time, FSX high to DX valid
FSX int
0 + D1(8)
14 + D2(8)
14
td(FXH-DXV)
ONLY applies when in data
ns
FSX ext
0 + D1(8)
25 + D2(8)
delay 0 (XDATDLY = 00b) mode
(1)
CLKRP = CLKXP = FSRP = FSXP = 0. If polarity of any of the signals is inverted, then the timing references of that signal are also
inverted.
(2)
Minimum delay times also represent minimum output hold times.
(3)
P = (1/SYSCLK4), where SYSCLK4 is an output clock of PLLC1 (see
Section 3.3) .
(4)
Use whichever value is greater. Minimum CLKR/X cycle times must be met, even when CLKR/X is generated by an internal clock
source.
(5)
The minimum CLKR/X cycle times are based on internal logic speed; the maximum usable speed may be lower due to EDMA limitations
and AC timing requirements. Use whichever value is greater.
(6)
C = H or L
S = sample rate generator input clock = P if CLKSM = 1 (P = SYSCLK3 period)
S = sample rate generator input clock = P_clks if CLKSM = 0 (P_clks = CLKS period)
H = CLKX high pulse width = (CLKGDV/2 + 1) * S if CLKGDV is even
H = (CLKGDV + 1)/2 * S if CLKGDV is odd
L = CLKX low pulse width = (CLKGDV/2) * S if CLKGDV is even
L = (CLKGDV + 1)/2 * S if CLKGDV is odd
CLKGDV should be set appropriately to ensure the McBSP bit rate does not exceed the maximum limit.
(7)
Extra delay from CLKX high to DX valid applies only to the first data bit of a device, if and only if DXENA = 1 in SPCR.
If DXENA = 0, then D1 = D2 = 0
If DXENA = 1, then D1 = 6P, D2 = 12P
(8)
Extra delay from FSX high to DX valid applies only to the first data bit of a device, if and only if DXENA = 1 in SPCR.
If DXENA = 0, then D1 = D2 = 0
If DXENA = 1, then D1 = 6P, D2 = 12P
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2009–2011, Texas Instruments Incorporated
Peripheral Information and Electrical Specifications
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