The following is from the Zenith service modules for the Z150/Z160 computers. /////////////////////////////////////////////////////////////////////////////// CPU BOARD CONFIGURATION For instructions on removing the card from the computer, refer to the Base Unit Service Module. DUAL INLINE PACKAGE SWITCHES Two dual inline package (DIP) switches, each containing eight individual switch sections, are used to select specific operation modes. Switch SW1 selects the I/O options and can be configured to select the number of 5.25-inch drive, columns in the display, base memory size, and tells the CPU if the optional 8087 coprocessor is installed. Switch SW2 selects the extended options and may be configured to select 50 or 60 Hz line frequency for the video display, manual or auto-boot of the disk drives, and informs the CPU of the presence of add-on memory. The setting of these switches is read by the CPU as either a logic zero (switch section in the closed "ON" position), or a logic one (switch section in the open "OFF" position). Figure 2.1 identifies and illustrates the physical configuration of both DIP switches SW1 and SW2. The configuration of the DIP switches is described in Tables 2.1 through 2.3. SW1 SW2 +------------------------------------+ +------------------------------------+ | ON | | ON | | ^ +-+ +-+ +-+ +-+ +-+ +-+ +-+ +-+ | | ^ +-+ +-+ +-+ +-+ +-+ +-+ +-+ +-+ | | | | | |*| | | | | | | |*| |*| |*| | | | |*| | | |*| |*| |*| | | | | |*| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | |*| | | |*| |*| |*| | | | | | | | | | | | |*| | | | | | | |*| |*| | | | | | +-+ +-+ +-+ +-+ +-+ +-+ +-+ +-+ | | | +-+ +-+ +-+ +-+ +-+ +-+ +-+ +-+ | | 0 1 2 3 4 5 6 7 | | 0 1 2 3 4 5 6 7 | +------------------------------------+ +------------------------------------+ Figure 2.1. DIP Switches Table 2.1. SW1 DIP Switch Configuration ------------------------------------------------------------------------------ Switch Section Function SWITCH SETTINGS ------------------------------------------------------------------------------ 0 Floppy Disks ON: No Floppy Drives Attached Attached OFF: Floppy Drives are Attached 1 8087 Installed ON: Not Installed OFF: 8087 Installed 2 and 3 Base Memory Size OFF, OFF: 64K NOTE: Sections 2 and 3 are always set to this position. 4 and 5 Column Display ON, ON: Reserved Type OFF, ON: 40 X 25 ON, OFF: 80 X 25 OFF, OFF: Monochrome Video 6 and 7 Number of 5.25-inch ON, ON: 1 Drive Drives Installed OFF, ON: 2 Drives ON, OFF: 3 Drives OFF, OFF: 4 Drives ------------------------------------------------------------------------------ Table 2.2. SW2 DIP Switch Configuration ------------------------------------------------------------------------------ Switch Section Function SWITCH SETTINGS ------------------------------------------------------------------------------ 0, 1, 2, Add-On Memory Size The DIP switches are configured to accommodate 3 and 4 the various CPU memory capacities as required for each computer model. (See Table 2.3.) 5 and 6 Select Boot Mode ON, ON: Manual Boot and Booted Drive OFF, ON: Autoboot Floppy ON, OFF: Autoboot Winchester OFF, OFF: Manual Boot 7 Line Frequency ON: 60 Hz Display Select for CRT OFF: 50 Hz Display* Screen Sweep *Not Recommended ------------------------------------------------------------------------------ Table 2.3. SW2 Memory Size Switch Section Settings --------------------------------------------------- 0 1 2 3 4 NUMBER OF BYTES --------------------------------------------------- ON ON ON ON ON = 64K ON OFF ON ON ON = 128K ON ON OFF ON ON = 192K ON OFF OFF ON ON = 256K ON ON ON OFF ON = 320K ON OFF ON OFF ON = 384K ON ON OFF OFF ON = 448K ON OFF OFF OFF ON = 512K ON ON ON ON OFF = 576K ON OFF ON ON OFF = 640K --------------------------------------------------- JUMPER CONNECTOR CONFIGURATION A row of jumper connectors is located in the center of the CPU card (Figure 2.2). The jumper connectors configure the monitor ROMs. The jumpers may be configured as follows: * A jumper connected between pins 5 and 10 informs the CPU that ROM 1 is a 256K device. * A jumper connected between pins 4 and 9 informs the CPU that ROM 1 is a 128K device. * A jumper connected between pins 3 and 8 informs the CPU that ROM 2 is a 256K device. * A jumper connected between pins 2 and 7 informs the CPU that ROM 2 is a 128K device. * A jumper connected between pins 1 and 6 informs the CPU that a RAM chip is installed into the ROM 2 socket. The card normally is supplied with no RAM installed. jumpers-----------+ | | ^ V V | +-+ +-+ top pins---> * |*| * |*| * bottom +-> * |*| * |*| * | +-+ +-+ V P203 Figure 2.2. Jumper Connections /////////////////////////////////////////////////////////////////////////////// MEMORY BOARD CONFIGURATION < no switches on the memory board . . . first page repeats CPU board memory > < switch settings . . . see above . . . . . . . . . . . . . . . . . . . . . > CONFIGURATION JUMPERS J401, J402, and J403 are configuration jumpers located on the memory card. J401 is used as a card-select jumper. If only one memory card is used, J401 should be positioned to the left away from the edge connector), marked "1st". If the system has two memory cards, position the jumper on the card to be designated as the first block of 320K-byte memory to "1st", and the jumper on the card containing the second block to the right, marked "2nd". If 256K RAM chips, as opposed to 64K, are used, only one card is used and J401 should be positioned to "1st". J402 and J403 on the initial card are used to assign the parallel output port to a desired I/O port address according to Table 2.2. Table 2.2. Parallel Port Address Selection -------------------------------------------- J403 J402 CONFIGURATION PORT -------------------------------------------- 0 0 Parallel Printer *3BC NOTE: Zenith manual doesn't say so, but 0=OUT and 0 1 Parallel Printer 378 1=IN. 1 0 Port Disabled N/A 1 1 Port Disabled N/A *This port corresponds to the monochrome display port on the IBM PC. -------------------------------------------- ///////////////////////////////////////////////////////////////////////////////