
SMJ320C6414, SMJ320C6415, SMJ320C6416
FIXEDPOINT DIGITAL SIGNAL PROCESSORS
SGUS050A JANUARY 2004 REVISED MARCH 2004
117
POST OFFICE BOX 1443
HOUSTON, TEXAS 772511443
MULTICHANNEL BUFFERED SERIAL PORT (McBSP) TIMING (CONTINUED)
switching characteristics over recommended operating conditions for McBSP (see Figure 51)
NO.
PARAMETER
MIN
MAX
UNIT
1
td(CKSH-CKRXH)
Delay time, CLKS high to CLKR/X high for internal CLKR/X generated
from CLKS input
1.4
10
ns
2
tc(CKRX)
Cycle time, CLKR/X
CLKR/X int
6.67§*
ns
3
tw(CKRX)
Pulse duration, CLKR/X high or CLKR/X low
CLKR/X int
C 1*
C + 1*
ns
4
td(CKRH-FRV)
Delay time, CLKR high to internal FSR valid
CLKR int
2.1
3
ns
9
td(CKXH-FXV)
Delay time, CLKX high to internal FSX valid
CLKX int
1.7
3
ns
9
td(CKXH-FXV)
Delay time, CLKX high to internal FSX valid
CLKX ext
1.7
9
ns
12
tdis(CKXH-DXHZ)
Disable time, DX high impedance following last data bit
CLKX int
3.9*
4*
ns
12
tdis(CKXH-DXHZ)
Disable time, DX high impedance following last data bit
from CLKX high
CLKX ext
2.1*
9*
ns
13
td(CKXH-DXV)
Delay time, CLKX high to DX valid
CLKX int
3.9 + D1#
4 + D2#
ns
13
td(CKXH-DXV)
Delay time, CLKX high to DX valid
CLKX ext
2.1 + D1#
9 + D2#
ns
14
td(FXH-DXV)
Delay time, FSX high to DX valid
FSX int
2.3
5.6
ns
14
td(FXH-DXV)
ONLY applies when in data
delay 0 (XDATDLY = 00b) mode
FSX ext
1.9
9
ns
*This parameter is not production tested.
CLKRP = CLKXP = FSRP = FSXP = 0. If polarity of any of the signals is inverted, then the timing references of that signal are also inverted.
Minimum delay times also represent minimum output hold times.
§ 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.
C = H or L
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)
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
CLKGDV should be set appropriately to ensure the McBSP bit rate does not exceed the maximum limit (see footnote above).
# 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 = 4P, D2 = 8P