MC68000 MOTOROLA [Motorola, Inc], MC68000 Datasheet - Page 320

• Manufacturer Part Number: MC68000
• Manufacturer: MOTOROLA [Motorola, Inc]

Electrical Characteristics
6.20 AC ELECTRICAL SPECIFICATIONS—GCI TIMING
GCI supports the NORMAL mode and the GCI channel 0 (GCN0) in MUX mode. Normal
mode uses 512 kHz clock rate (256K bit rate). MUX mode uses 256 x n - 3088 kbs (clock
rate is data rate x 2). The ratio CLKO/L1CLK must be greater than 2.5/1 (see Figure 6-21).
6-32
NOTES:
1.The ratio CLKO/L1CLK must be greater than 2.5/1.
2. Condition C L = 150 pF. L1TD becomes valid after the L1CLK rising edge or L1SY1, whichever is later.
3.SDS1–SDS2 become valid after the L1CLK rising edge or L1SY1, whichever is later.
4.Schmitt trigger used on input buffer.
5.Where P = 1/CLKO. Thus, for a 16.67-MHz CLKO rate, P = 60 ns.
Num.
281A
280
281
282
280
281
282
283
284
285
286
287
288
289
290
291
292
293
L1CLK GCI Clock Frequency (Normal Mode) (see
Note 1)
L1CLK Clock Period Normal Mode (see Note 1)
L1CLK Width Low/High Normal Mode
L1CLK Rise/Fall Time Normal Mode (see Note 4)
L1CLK (GCI Clock) Frequency (MUX Mode) (see
Note 1)
L1CLK Clock Period MUX Mode (see Note 1)
L1CLK Width Low MUX Mode
L1CLK Width High MUX Mode (see Note 5)
L1CLK Rise/Fall Time MUX Mode (see Note 4)
L1SY1 Sync Setup Time to L1CLK Falling Edge
L1SY1 Sync Hold Time from L1CLK Falling Edge
L1TxD Active Delay (from L1CLK Rising Edge) (see
Note 2)
L1TxD Active Delay (from L1SY1 Rising Edge) (see
Note 2)
L1RxD Setup Time to L1CLK Rising Edge
L1RxD Hold Time from L1CLK Rising Edge
Time Between Successive L1SY1in
SDS1–SDS2 Active Delay from L1CLK Rising Edge
(see Note 3)
SDS1–SDS2 Active Delay from L1SY1 Rising Edge
(see Note 3)
SDS1–SDS2 Inactive Delay from L1CLK Falling
Edge
GCIDCL (GCI Data Clock) Active Delay
Characteristic
MC68302 USER’S MANUAL
SCIT Mode
Normal
P+10
1800 2100 1800 2100 1800
Min
192
16.67 MHz
840
150
—
—
—
—
64
55
30
50
20
50
10
10
10
0
0
0
6.668
1450
Max
512
100
100
—
—
—
—
—
—
—
—
—
—
—
90
90
90
50
P+10
Min
192
840
150
—
—
—
—
64
20 MHz
55
25
42
17
42
10
10
10
0
0
0
6.668
1450
Max
512
—
—
—
—
—
—
—
—
—
—
—
85
85
75
75
75
42
P+10
Min
192
840
150
—
—
—
—
64
55
20
34
14
34
25 MHz
7
7
7
0
0
0
6.668
2100
1450
Max
512
—
—
—
—
—
—
—
—
—
—
—
70
60
34
70
60
60
MOTOROLA
L1CLK
L1CLK
MHz
Unit
kHz
ns
ns
ns
ns
ns
ns
ns
ns
ns
ns
ns
ns
ns
ns
ns
ns
ns