DM41X Progs - Make It Tea

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====== DM41X Progs ======

===== TI : calculate 65c22 Timer values for tone generation =====

==== Counter calculation ====

The required count is calculated from ''Φ<sub>2</sub>'' and the audio frequency required.

Count (decimal) 

{ Φ<sub>2</sub> / ( 2 x F ) } - 2

for 1000Hz  and a 1MHz Φ<sub>2</sub> :

Count = { 1,000,000 / ( 2 X 1000 ) } - 2 = 498

498d -> $01F2

Run as <key>XEQ</key><key>ALPHA</key>''TI''<key>ALPHA</key>

Prompt ''F'' for required audio tone frequency.

Enter freq 

<key>R/S</key> 

Result is the 2-byte value for T1CL & T1CH

e.g.

<key>XEQ</key><key>ALPHA</key>''TI''<key>ALPHA</key>

  1000 

<key>R/S</key> 

Result:

  $001F2

The Counter should be set to 

  T1CH = $01
  T1CL = $F2

Entered as follows (make sure you're in DECS mode in Ladybug while entering the program - otherwise the ''1000000'' won't be interpreted correctly). When viewing/editing the program later it will look different! 

<code>
LBL ¬TI
DECS
WSIZE 20
¬ F
PROMPT
STI 01
1000000
ENTERI
LDI 01
2
x
/
2
-
HEXS
RTN
</code>
===== BFil =====

++++ Butterworth HPF/LPF Filter designer |

<code>
LBL ¬BFIL
SF 00
¬MHZ ?
PROMPT
1 E6
*
STO 11
¬N
PROMPT
x<0?
CF 00
STO 10
XEQ 06
LBL 01
RCL 12
INT
XEQ 00
FS? 00
1/x
STO IND 12
ISG 12
GTO 01
¬COEFFICIENTS
FIX 3
STOP
ENG 3
XEQ 06
LBL 02
RCL 12
INT
RCL IND 12
RCL 11
2
*
PI
*
/
STO IND 12
ISG 12
GTO 02
XEQ 06
LBL 03
RCL 12
INT
2
/
FRC
FS? 00
GTO 09
GTO 10
LBL 09
¬HPF
x=0?
GTO 05
GTO 04
RTN
LBL 10
¬LPF
x=0?
GTO 04
GTO 05
RTN
LBL 04
RCL IND 12
50
*
STO IND 12
ISG 12
GTO 03
RTN
LBL 05
RCL IND 12
50
/
STO IND 12
ISG 12
GTO 03
RTN
LBL 06
RCL 10
ABS
1000
/
1
+
STO 12
RTN
LBL 00
2
*
1
-
180
*
RCL 10
ABS
2
*
/
SIN
2
*
RTN
END
</code>


++++

==== Examples ====

=== 5MHz 5-pole LPF ===

<key>XEQ</key><key>ALPHA</key><key>BFIL</key><key>ALPHA</key>

  MHZ ? 

<key>5</key> <key>R/S</key>

  N

''Order/poles = N''

''Positive for HPF''

''Negative for LPF''

''5 pole LPF = -5'' 

<key>5</key><key>CHS</key><key>R/S</key>

  COEFFICIENTS
  0.618

(at this point you can <key>RCL 01</key> etc. up to <key>RCL 05</key> to see the calculated Butterworth Coefficients)

  * R01 : 0.618
  * R02 : 1.618
  * R03 : 2.000
  * R04 : 1.618
  * R05 : 0.618


<key>R/S</key>

  LPF
  393.5 -12

The calculated component values are now in Reg 01 - Reg 05

  * R01 : 393.5pf
  * R02 : 2.575uH
  * R03 : 1.273nF
  * R04 : 2.575uH
  * R05 : 393.5pF


=== 1MHz 7 pole HPF ===


<key>XEQ</key><key>ALPHA</key><key>BFIL</key><key>ALPHA</key>

  MHZ ? 

<key>1</key> <key>R/S</key>

  N

''Order/poles = N''

''Positive for HPF''

''Negative for LPF''

''7 pole HPF = 7'' 

<key>7</key><key>R/S</key>

  COEFFICIENTS
  2.247

(at this point you can <key>RCL 01</key> etc. up to <key>RCL 07</key> to see the calculated Butterworth Coefficients)

  * R01 : 2.247
  * R02 : 0.802
  * R03 : 0.555
  * R04 : 0.500
  * R05 : 0.555
  * R06 : 0.802
  * R07 : 2.247


<key>R/S</key>

  HPF
  17.88 -06

The calculated component values are now in Reg 01 - Reg 07

  * R01 : 17.88uH
  * R02 : 2.553nF
  * R03 : 4.416uH
  * R04 : 1.592nF
  * R05 : 4.416uH
  * R06 : 2.553nF
  * R07 : 17.88uH

===== Page Info =====

Page created Thu May 26 18:35:00 2022 by John Pumford-Green

Page last updated: ~~LASTMOD~~

{{tag>dm41x calculator}}




--- //John Pumford-Green 24/04/23 16:07//


===== Further Information =====


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