RCA RMB-167 manual Moving RMON167 to Eprom, Eprom CFG1

Page 16

 

 

Address Range

Jumpers

0-7FFFh

 

8000h-FFFFh

inserted

 

 

 

none

RAM

 

RAM

CFG0

EPROM

 

RAM

CFG1

RAM

 

EPROM

CFG0 and

EPROM

 

EPROM

CFG1

 

 

 

The EPROM at low memory may contain start-up code which is executed upon reset. In this case the jumper at P0.4 must be removed so that the microcontroller does not enter the bootstrap loader mode. The microcontroller simply starts executing from address 0.

With the jumpers CFG0 or CFG1 (or both) installed, the RMB-167 may still be bootstrapped. Again, the jumper P0.4 must be installed. This forces the SAB-C167 to enter the bootstrap mode upon reset. The bootstrap sequence terminates with a software reset instruction which starts executing the program starting at address 0. With CFG0 installed, this is the beginning of EPROM. That is, upon bootstrap, the code in EPROM is executed. While possible, first bootstrapping and then executing the code in EPROM is somewhat superfluous since any initialization code of the bootstrap loader may be placed in EPROM.

5.4Moving RMON167 to EPROM

As an example of placing a valid program in EPROM, consider modifying the monitor program RMON167 as given below. It is assumed that the lower 32K of memory is EPROM, and the higher 32K is RAM. The origin of the program is changed to 1000h. Note that the monitor needs buffers to store the commands and the parameters. These buffers are defined to occupy the beginning of RAM at 8000h. Also, the greeting message is changed to indicate that it is the EPROM version of the monitor.

Only the beginning few instructions and the greeting message are changed. Namely,

1.The buffers are moved to 8000h and 8020h, respectively,

2.Jump statements are placed at RESET and NMI vectors,

3.The origin of the monitor program is moved to 1000h

4.The initialization to CPS is now accomplished by an inter-segment jump to 1010h,

5.And finally, the greeting message is changed.

Also note that the address of register SYSCON is different in the SAB80C166 and SAB C167 microcontrollers. The monitor program must be assembled by specifying the C167 register definitions. The program listing follows.

CODE0 section code AT 0000h

;r15 is used for flags:

;bit 0 - error

;1 - dash

;2 - equal

;3 -

;---------------------------------------------------

;--- monitor system variables ---

-10-

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Contents USER’S Guide Page Page Warranty Table Of Contents 10.1.1 Hardware READS166 Evaluation Software OverviewParts List Software Installation, READS166 SoftwareSystem Requirements Third Party SoftwareConnections, Jumper Settings START-UPSoftware Initialization Serial NumberBootstrapping Verifying that the Monitor is Loaded A D S C O M M a N D STroubleshooting Hardware Set-upSoftware Set-up PC set-upPower Operating NotesSerial port Jumper SelectionMemory Options RAM Memory OptionsEprom Memory Options Alternate Memory Map with Eprom in Low MemoryMoving RMON167 to Eprom Eprom CFG1Rstisr Syscon is 89h on the 167 dw 089E6h Dw 0F800h Nop Mov GAL Equations Default GAL Equations1 U1 Equations U2 Equations Alternate GAL Equations1 U1 Equations For Eprom In Low Memory 2 U2 Equations For Eprom In Low Memory Equations JP6 System Header Signal Pins SignalHeaders and Jumpers System and I / O HeadersJP7 Input/Output Header Signal 166 JP2 JP7Pins JP8 Extra Input/Output Header of the RMB-167 SignalSignal RMB-167 Analog-to-Digital Converter Reference Jumpers Bootstrapping S0RIRDiswdt Einit Mov R1, #0A55Ah Minimal Monitor Port Configuration MON167 MonitorDownload HEX file HelpPort Data Word MemoryREADS166 Version READS166 V3.00 ConceptsArchive Projects Executable ProjectsModule Circuit Diagrams
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