SPRS079E – OCTOBER 1998 – REVISED AUGUST 2000
54
POST OFFICE BOX 1443
•
HOUSTON, TEXAS 77251–1443
multichannel buffered serial port timing
timing requirements for McBSP [H=0.5t
c(CO)
]
†
(see Figure 28 and Figure 29)
MIN
MAX
UNIT
tc(BCKRX)
Cycle time, BCLKR/X
BCLKR/X ext
4H
ns
tw(BCKRX)
Pulse duration, BCLKR/X high or BCLKR/X low
BCLKR/X ext
2H–2
ns
t
Setup time external BFSR high before BCLKR low
BCLKR int
8
ns
tsu(BFRH-BCKRL)
Setup time, external BFSR high before BCLKR low
BCLKR ext
1
ns
t
Hold time external BFSR high after BCLKR low
BCLKR int
0
ns
th(BCKRL-BFRH)
Hold time, external BFSR high after BCLKR low
BCLKR ext
3
ns
t
Setup time BDR valid before BCLKR low
BCLKR int
5
ns
tsu(BDRV-BCKRL)
Setup time, BDR valid before BCLKR low
BCLKR ext
0
ns
t
Hold time BDR valid after BCLKR low
BCLKR int
0
ns
th(BCKRL-BDRV)
Hold time, BDR valid after BCLKR low
BCLKR ext
4
ns
t
Setup time external BFSX high before BCLKX low
BCLKX int
7
ns
tsu(BFXH-BCKXL)
Setup time, external BFSX high before BCLKX low
BCLKX ext
0
ns
t
Hold time external BFSX high after BCLKX low
BCLKX int
0
ns
th(BCKXL-BFXH)
Hold time, external BFSX high after BCLKX low
BCLKX ext
3
ns
tr(BCKRX)
Rise time, BCKR/X
BCLKR/X ext
8
ns
tf(BCKRX)
Fall time, BCKR/X
BCLKR/X ext
8
ns
† CLKRP = CLKXP = FSRP = FSXP = 0. If the polarity of any of the signals is inverted, then the timing references of that signal are also inverted.
switching characteristics for McBSP [H=0.5t
c(CO)
]
†
(see Figure 28 and Figure 29)
PARAMETER
MIN
MAX
UNIT
tc(BCKRX)
Cycle time, BCLKR/X
BCLKR/X int
4H
ns
tw(BCKRXH)
Pulse duration, BCLKR/X high
BCLKR/X int
D – 2‡
D + 2‡
ns
tw(BCKRXL)
Pulse duration, BCLKR/X low
BCLKR/X int
C – 2‡
C + 2‡
ns
t
Delay time BCLKR high to internal BFSR valid
BCLKR int
–2
2
ns
td(BCKRH-BFRV)
Delay time, BCLKR high to internal BFSR valid
BCLKR ext
3
9
ns
t
Delay time BCLKX high to internal BFSX valid
BCLKX int
0
4
ns
td(BCKXH-BFXV)
Delay time, BCLKX high to internal BFSX valid
BCLKX ext
8
11
ns
t
Disable time, BCLKX high to BDX high impedance following last data
BCLKX int
–1
4
ns
tdis(BCKXH-BDXHZ)
Disable time, BCLKX high to BDX high im edance following last data
bit of transfer
BCLKX ext
3
9
ns
t
Delay time BCLKX high to BDX valid
DXENA
0§
BCLKX int
0¶
7
ns
td(BCKXH-BDXV)
Delay time, BCLKX high to BDX valid
DXENA = 0§
BCLKX ext
3
11
ns
t
Delay time, BFSX high to BDX valid
BFSX int
–1¶
3
ns
td(BFXH-BDXV)
ONLY applies when in data delay 0 (XDATDLY = 00b) mode
BFSX ext
3
13
ns
† CLKRP = CLKXP = FSRP = FSXP = 0. If the polarity of any of the signals is inverted, then the timing references of that signal are also inverted.
‡ T = BCLKRX period = (1 + CLKGDV) * 2H
C =
BCLKRX low pulse width = T/2 when CLKGDV is odd or zero and = (CLKGDV/2) * 2H when CLKGDV is even
D =
BCLKRX high pulse width = T/2 when CLKGDV is odd or zero and = (CLKGDV/2 + 1) * 2H when CLKGDV is even
§ The transmit delay enable (DXENA) and A–bis mode (ABIS) features of the McBSP are not implemented on the TMS320VC5402.
¶ Minimum delay times also represent minimum output hold times.
