ra8806 RAIO Technology Inc., ra8806 Datasheet - Page 65

• Manufacturer Part Number: ra8806
• Description: Two Layers Character/graphic Lcd Controller
• Manufacturer: RAIO Technology Inc.

Preliminary Version 1.2
RAiO
TECHNOLOGY INC.
6-8-2 Busy
If user use a 6MHz X’tal for system clock, the Clock Stable Time is about 3~3.5ms and t
Example-2:
The Figure 6-33 is an example of INT timing for Key-Scan event.
The “De-bounce Time” is set by REG[A0h] Bit[5:4], and the t
depends on the setting of REG[A0h] Bit[2:0].
Additionally, because the status bit will not be cleared to 0 automatically. So user must manually
clear it after processing the interrupt routine.
The RA8806 also provides a “BUSY” signal. When Busy Flag is “1”, which means RA8806 is in busy
state that RA8806 couldn’t access data from DDRAM. Two busy conditions are provided. One is
Scan Busy and another is Memory Write Busy. The detail explains is as follows.
Scan Busy:
When LCD panel displays, RA8806 scan circuit will access the DDRAM. If another DDRAM access
cycle happens. It will cause the data lose in one of them. So when scan circuit is active, it causes a
busy condition, called Scan Busy. Figure 6-34 shows the data flow diagram of scan circuit and MPU
memory access cycle. Figure 6-35 is same as Figure 6-15 to show RA8806 scan waveform. It
describes the condition that RA8806 scan the display for each COM line. The COM scan time is
combined with an Idle time and a Scan time. The Idle time period can be set by register ITCR. The
Scan period is the time of Scan Busy. Also accessing data at Scan Busy time will cause the scan
data lose. But it will not cause a fatal error. The scan data lose will cause the display defect. But if
it’s not too frequent, the defect will not infect the display too much.
Key-Scan
t
t
INTST
INTST
Event
INT
= Clock Stable Time + 1024*t
= De-bounce Time + t
Figure 6-33 : Interrupt Timing(2)
CKEY
65/184
t
INTST
C
Two Layers Character/Graphic LCD Controller
CKEY
is the Key-Scan Cycle that
www.raio.com.tw
RA8806
C
is 167ns.