Toshiba H1 Series Data Book page 108

Sample3) Calculation example for CPU + LDMA + ARDMA
Conditions:
CPU operating speed(f
Display RAM
Display size
Display quality
Refresh rate
SDRAM auto refresh
Calculation example:
t (LDMA)
STOP
LHSYNC [period:s]
Since SDRAM is auto-refreshed once or less in 5.47 [ μ s]:
t (ARDMA)
STOP
CPU bus stop rate
) : 60 MHz
SYS
: 16-bit external SDRAM
: QVGA (320seg × 240com)
: 65536 colors (TFT)
: 70 Hz (including 20 clocks of dummy cycles)
: Every 936 states (15.6 μ s)
= ((SegNum × K / 8) × t ) + (8 / f
LRD
= ((320 × 16 / 8) × 1 / f [Hz] / 2) + (8 / f
SYS
= ((640) × 16.67 [ns] / 2) + 133.33 [ns]
= 5.47 [ μ s]
= 1/70 [Hz] / (COM + 20 = 260) = 54.95 [ μ s]
= 2 / f [Hz] = 33.33 [ns]
SYS
= t
(LDMA ･ ARDMA) [s] / LHSYNC [period:s]
STOP
= (5.47 [ μ s] + 33.33 [ns]) / 54.95 [ μ s] = 10.01 [%]
92CZ26A-105
[Hz])
SYS
[Hz])
SYS
TMP92CZ26A