25

6399A–DRMSD–13-Oct-08

ATSAM2553

Note: There are three possible values for Key page.

0: Value sampled at Row4 = 0, Row3 = 0

1: Value sampled at Row4 = 0, Row3 = 1

2: Value sampled at Row4 = 1, Row3 = 0

3: Not used.

12.5.1

KBD Status (I/O add OCH Read-only)

• D[7] KRQ flag = 1 indicates that a key-on or key-off has been detected and that the P16

service is requested. This flag is automatically cleared by a write to data H for the detected

key.

• D[6:0] specify which keyboard key is requesting the service, valid only if KRQ flag = 1. Key nb

range from 0 to 87.

• D[9:8] specify the Key page

12.5.2

RAM Add (I/O add OCH Write-only)

• D[6:0] RAM address

• D[7] don't care

• D[9:8] Key page

“i” refers to the Mki or Bri signal number which ranges from 0 to 10. For example, the information

regarding the key at row 2, column MK5/BR5, will be found at RAM address 8*5+2=42.

The scanning hardware cycles the row[2:0] signals from 0 to 7 to the output pins in 41.6 µs (5.2

µs per row).

12.5.3

RAM Data (I/O add ODH Read/Write)

Data[10:0]

I/O add ODH, Data[10:0]

Data[15:11]

don't care

Scanning RAM data format:

Key Page

Add

Index

Content

Value: 0,1,2

00H to 57H

8*i+row[2:0]

Key velocity and status

Don't-care

58H to 5FH

row[2:0]

Led data

Don't-care

60H to 6FH

row[3:0]

Switch status

Don't-care

70H to 7FH

row[3:0]

ADC value

Bit–>

10

9876543210

Key velocity & status

SRQ

ON

BUSY

VEL

LED data

MK10

MK9

MK8

MK7

MK6

MK5

MK4

MK3

MK2

MK1

MK0

Switch data

BR10

BR9

BR8

BR7

BR6

BR5

BR4

BR3

BR2

BR1

BR0

ADC status

X

X

X

ADC DATA