Related Manuals for North Star RAM-16-A
Summary of Contents for North Star RAM-16-A
- Page 1 IskxttiSld^ NorHnSbiCom puters Inc. 2547 Ninth Street Berkeley, Ca, 94710 North Star 16K Ram Board Copyright® 1978, North Star Computers, Inc. RAM-16-DOC R e v is io n 2...
-
Page 2: Table Of Contents
Limited W a r r a n t y ..... . . Out of Warranty Repair ....RAM-16-A Parts List ......Parity Option Parts List ..... Assembly Information .. -
Page 3: Introduction
64K bytes of RAM to be used in the computer, and also facilitates special software applications such as time sharing . If you have purchased the RAM-16-A as a kit, then first skim the entire manual. Be sure to carefully read the Assembly Information section before beginning assembly. -
Page 4: Limited Warranty
90 days from date of purchase. If such defects occur, North Star Computers, Inc. will repair the defect at no cost to the purchaser. This warranty does not extend to defects resulting from improper use or assembly by purchaser, nor does it cover transportation to the factory. -
Page 5: Ram-16-A Parts List
RAM-16-A PARTS LIST RAM-16-A Manual RAM-16-A printed circuit board, 5“ x 10" 20-pin IC sockets 16-oin IC sockets 14-pin IC sockets 14-pin DIP header 8-position DIP switch delay line, DDU-4-7781 or STTLDM-400 +5 volt regulator, 7805 or 340T-5 +12 volt regulator, 7812 or 340T-12... -
Page 6: Parity Option Parts List
2.2 uF .047uF ceramic disc PARITY OPTION PARTS LIST 74LS109 IC 74LS280 IC 75452 IC (8-pin) 4027-3 IC (MOS) 16-pin IC sockets 14-pin IC sockets 8-pin IC socket 220 ohm 1/4W resistor (red-red-brown) North Star 16K RAM BOARD... -
Page 7: Assembly Information
1 indication on the PC board layout legend. (Refer to figure 1A to identify pin 1 on an IC socket.) To solder IC sockets, first solder just two opposite corner pins North Star 16K RAM Board... - Page 8 Note that in North Star kits, IC's can be found on styrene pads in positions corresponding to their intended locations on the PC board.
- Page 9 MOS INTEGRATED CIRCUIT HANDLING Some North Star PC boards use some MOS-type IC's. These parts are identified as such in the instructions. MOS devices can be damaged by static electricity discharge, so special handling is necessary to protect them. Handle MOS devices as little as possible and avoid touching the pins.
- Page 10 € B O Resistor Regulator (To-220) Dipped Quick-Connect Ceramic Dipped Dipped Disc Mylar Mica Tantalum Capacitor Capacitor Capacitor Capacitor 1C Socket Integrated Circuit (1C) D I P Header Figure 1 A. Identification and orientation of components.
-
Page 11: Ram Board Assembly
M / R5 (V) R6 yel-vio-brn 1/4W brn-blk-org 10 K 1/4W (\Ä R7 ( x > J R8 1/4W red-red-red 2.2K red-red-red 2.2K 1/4W org-org-brn 1/4W ( J ) 2.2K red-red-red 1/4W red-red-red 2.2K 1/4W North Star 16K RAM Board... - Page 12 + lead of each capacitor into the hole marked " + • * on the layout legend. The + lead is sometimes indicated by a red dot on the capacitor. Refer to the North Star 16K RAM BOARD...
- Page 13 Orient the delay line so that pin 1 (indicated by a dot or " ' " “IN“) is inserted in pin 1 of the socket. Install the 28 TTL integrated circuits (all but the memory IC's). Be careful to orient each IC so that pin 1 is North Star 16K RAM Board...
- Page 14 IC, and that no pins are outside the socket. lrsx " R21 . • If you are assembling the RAM-16-A board for use with the HORIZON computer, install the three “G" jumpers at locations 2E, 5E, and 6E by soldering with a piece of resistor snipping.
- Page 15 A. Connect pin 1 to pins 2 and 3. B. Connect pin 6 to pin 7. This configuration of the header is for use of the RAM-16-A board with a Z80 or Z80A microprocessor in an application where bank switching is not needed.
-
Page 16: Ram Board Checkout
If your S-100 bus computer has a control panel, then check out control panel operation of the RAM-16-A as described in this step. Otherwise, skip to step C2. - Page 17 TM command in the North Star Monitor), then use the program listed in Appendix 2. If the RAM-16-A does not fail the memory test after several hours of operation, then the board is operational and you may skip the remaining checkout steps.
- Page 18 (-210ns thrice,11T) CAS-D/ 9D pin 15 (-210ns thrice,11T) Note 1: (-100ns,11T) with Z80A, '(-210ns,11T) with 8080. Note 2: Sometimes (-225ns,11T) and sometimes (-225ns twice,11T). If the signals are not as listed, refer to the schematic North Star 16K RAM BOARD...
- Page 19 RAM-16-A board in the computer motherboard. F. Turn on the computer power. The repeated executions of the RST 7 instruction should fill the entire RAM-16-A board with alternating bytes containing 3A hex and 00 (resulting from the stack pushes of the RST instruction).
- Page 20 Note 4: Four pulses per loop, two fetches and two stores. H. Check the following data output signals on the RAM-16-A. you are using an oscilloscope, then trigger on ID pin 11 or the upper end of R10 at 12E (SMI) on the RAM-16-A. Location Description Signal 1 0 .
-
Page 21: Parity Option Assembly And Checkout
PARITY OPTION ASSEMBLY AND CHECKOUT Skip this section if you did not purchase a parity option (RAM- 16-PAR) for your RAM-16-A board. If you are installing the parity option, first be sure the board is completely checked out without the parity option. - Page 22 If the LED did not light, then locate and correct the problem before continuing. Pll. Power up the computer with the RAM-16-A board installed in the motherboard. Use a program such as the standard HORIZON DOS initialization to store into each byte on the board, to clear all incorrect parity bytes.
-
Page 23: Configuration
CONFIGURATION This section describes each of the RAM-16-A options which must be configured before use of the RAM-16-A. Note that configuration of the parity logic and bank switching logic is described in later sections. ADDRESS SELECTION Address selection for the RAM-16-A is determined by the switches at location 7A. - Page 24 2E, 5E, and 6E. PHANTOM MEMORY The RAM-16-A board can be used with some area of ROM superimposed over the address region of the board. If the PH jumper (near location 4E) is installed, then a memory reference to the board will be inhibited if the backplane signal PHANTOM (motherboard pin 67) is LOW.
-
Page 25: Using The Parity Option
DIP header at location 7D will determine which bit (of bits 1-7) in the control value, if 1, will cause arming or disarming of the parity logic for the RAM-16-A. (Arming or disarming the parity error logic also resets the parity error flip-flop.) - Page 26 (including the parity bit), and not all bytes will have correct parity. Before arming the parity logic, clear all bytes to correct parity by storing into all bytes of RAM. Note that the standard HORIZON DOS initialization performs this function. North Star 16K RAM BOARD...
-
Page 27: Using Bank Switching
USING BANK SWITCHING At any time, a RAM-16-A may be in one of two "states": In this state the board will respond to memory references made to the addresses specified by the address selection switches. In this state the board will ignore all memory references from the processor. -
Page 28: Theory Of Operation
THEORY OF OPERATION The RAM-16-A consists of a 4 by 8 (4 by 9 if parity is included) array of 200ns 4K dynamic 4027 RAM chips plus additional circuitry which performs the necessary support functions. Refer to the schematic drawings while reading the following theory of operation. - Page 29 WAITING-REFRESH cycle. This type of cycle therefore maintains refresh activity when the reset switch is depressed, during long wait states (control panel or North Star disk controller), or when an 8080 is halted. See the next section for more information.
- Page 30 BOARD SELECT AND CHIP SELECT The RAM-16-A occupies two 8K regions of a 64K byte address space. Address bits A15, A14, and A13 ct o to a one-of-eight decoder, the outputs of which go to eight switches.
- Page 31 The AND of PARITY-ARM and PARITY-ERROR goes to another driver, the output of which the user may wire to one of the eight vectored interrupts, to PINT, or to N M I . The CLR signal initializes the PARITY-ERROR and PARITY-ARM flip- flops off. North Star 16K RAM Board...
-
Page 32: Special Dma Applications
These modifications are only needed if the RAM-16-A is being used with a Z80 or Z80A processor board. (To use the RAM-16-A with a special DMA device in an 8080-based system, it is necessary only to install a resistor as described in step Dl below.) D l . -
Page 33: Appendix 1: Pulse Signal Detection
2. Use a logic probe that detects pulses. 3. If the RAM-16-A is being assembled for use with a HORIZON, then use a counter on the motherboard to divide the frequencies down to the audio range and then play the result through a hi-fi amplifier. -
Page 34: Appendix 2: Memory Test Program
STEP MSB OF PTR 0030 7A MOV A,D TEST MSB OF PTR 0031 E60F ANI 17Q DONE WITH 4K REGION? 0033 C21E00 LOOP IF NOT AT 4K BOUNDARY JNZ RFL 0036 END OF READ LOOP 0036 North star 16K RAM BOARD... - Page 35 005E B3 ORA E CONTINUE TEST 005F C24D00 JNZ RBL LOOP IF NOT AT END OF 4K 0062 0C INR C CHANGE PATTERN 0063 C20400 JNZ PASS ALL DONE WITH TEST 0066 C9 00 67 North Star 16K RAM Board...
- Page 36 DB 3370 00FA EF DB 357Q 00FB F7 DB 367Q 00FC FB DB 3730 00FD FD DB 3750 0 0FE FE DB 3760 00FF FF DB 3770 MUST BE END OF 256-BYTE BLOCK 010 0 North Star 16K RAM BOARD...
-
Page 37: Appendix 3: Organization Of Ram Chip Array
The column 15A-15D contains bit 2 (the 04 hex bit) . The column 16A-16D contains bit 3 (the 08 hex bit) . The column 17 A-17 D contains bit 7 (the 80 hex bit) . North Star 16K RAM Board... -
Page 38: Schematic Drawings
North Star 16K RAM BOARD... - Page 39 North Star 16K RAM Board...
- Page 40 North Star 16K RAM BOARD...
- Page 41 V ' 3 — SI4T REDUCE NOISE ®> — ^'G^ ------ PARITY CHECK OPTION, POWER öf (cs\°ae, N o rth S t a r C o m p u te r s , X n c . North Star 16K RAM Board...
Need help?
Do you have a question about the RAM-16-A and is the answer not in the manual?
Questions and answers