Motorola M6800 manual

Page 28

MPU-28

82510 = 11001110012

 

 

 

 

 

 

= 1x20 +Ox21 +0x22 +lx23

+1x24

+1x25 +0x26

+0x27

+lx28

+1x29

= lxl

+0x2

+0x4

+lx8

+1x16

+lx32 +0x64

+0x128

+1x256 +1x512

= 1

+ 0

+ 0

+ 8

+ 16

+ 32 + 0

+ 0

+ 256

+ 512

= 82510

Or taking 147l8 and representing each digit by its binary

representation, we get 1=001, 4=100, 7=111 & 1 = 001 which when put together

equal 001100111001. Notice this is the same bit pattern as when we converted

from base 10 to base 2. Now if we group this into three groups of four bits

and then convert each group to its hex counterpart, we will have the number

of 82510 represented in hex. 001100111001 = 0011 0011 1001 = 33916. Notice

this agrees with the result when we converted directly to hex from one base

10 number.

In summary, lets take the situation when an MPU 6800 8 bit register

contains all 1's.

11111111

=

1x20 + lx21 + lx22

+ 1x23

+ 1x24

+ 1x25

+

1x26 + 1x27

 

=

1x1

+

1x2 + 1x4

+ 1x8 + 1x16 + 1x32

+

1x64 +

1x128

 

=

1

+ 2

+ 4

+ 8

+ 16

+ 32

+

64 +

128

 

=

25510 or

 

 

 

 

 

 

 

11111111

= 11 111 111

= 7x80

+ 7x81

+ 7x82

 

 

 

 

 

=

3

7

7

 

 

 

 

=7x1 + 7x8 + 3x64

=7 + 56 + 192

=25510 or

11111111 = 1111 1111

=F F16

=15x160 + 15x161

=15x1 + 15x16

=

15

+ 240

=

25510

 

Image 28
Contents MPU-1 Introduction MPU-2 MPU-3 MPU-4 MPU-5 BIT N0 Function MPU-7 Data BUS Enabledbe MPU-8READ/WRITE R/W Valid Memory AddressvmaMPU-9 NON-MASKABLE InterruptnmiBUS Available BA THREE-STATE Control TSC Address BUS AO/A15ABA INSADC INXPage MPU-14 Summary of MPU Operation Reset Sequence IRQ Sequence NMI Sequence RTI ExecutionSWI Instruction Page Page Page Page Page Page Page Page