TMS320C25, TMS320E25
SPRS010B— MAY 1987— REVISED NOVEMBER 1990
POST OFFICE BOX 1443 HOUSTON, TEXAS 77001
32
SERIAL PORT TIMING
switching characteristics over recommended operating conditions (see Note 3)
PARAMETER MIN TYP MAX UNIT
td(CH-DX) DX valid after CLKX rising edge (see Note 10) 75 ns
td(FL-DX) DX valid after FSX falling edge (TXM = 0, see Note 10) 40 ns
td(CH-FS) FSX valid after CLKX rising edge (TXM = 1) 40 ns
NOTES: 3. Q = 1/4tc(C).
10. The last occurrence of FSX falling and CLKX rising.
timing requirements over recommended operating conditions (see Note 3)
MIN NOM MAX UNIT
tc(SCK) Serial port clock (CLKX/CLKR) cycle time200 ns
tf(SCK) Serial port clock (CLKX/CLKR) fall time 25ns
tr(SCK) Serial port clock (CLKX/CLKR) rise time 25ns
tw(SCK) Serial port clock (CLKX/CLKR) low pulse duration (see Note 11) 80 ns
tw(SCK) Serial port clock (CLKX/CLKR) high pulse duration (see Note 11) 80 ns
tsu(FS) FSX/FSR setup time before CLKX/CLKR falling edge (TXM = 0) 18 ns
th(FS) FSX/FSR hold time after CLKX/CLKR falling edge (TXM = 0) 20 ns
tsu(DR) DR setup time before CLKR falling edge 10 ns
th(DR) DR hold time after CLKR falling edge 20 ns
The serial port was tested at a minimum frequency of 1.25 MHz. However, the serial port was fully static but will properly function down
to fsx = 0 Hz.
Value derived from characterization data and not tested.
NOTES: 3. Q = 1/4tc(C).
11. The duty cycle of the serial port clock must be within 40-60%.
ADVANCE INFORMATION