Sharp PC-1401

The Sharp PC -1401 published in 1984 was the first programmable in BASIC pocket computer by Sharp with integrated scientific calculators.

• 3.1 Pin Assignment

Modes

In addition to the existing in previous Pocket computers programming mode and run mode, a calculator mode is the PC -1401 is still available, in which the computer as a calculator behaves. Further, a statistical mode, which supports, inter alia, linear regression.

In previous models, calculations could be performed only on BASIC command line. Due to the calculator keypad to enter the width of the LC display was limited to 16 characters.

Type variants

PC -1401

The PC -1401 has 4,125 KByte static RAM, of which 3.5 KB for programs and variables are available. Variables A through Z were independent of available, they were applied statically. The memory has been realized by two CMOS RAM chips to 16 Kbps ( 2 Kbytes ). By replacing one of these building blocks by an 8 - Kbyte RAM module ( SMD), the storage capacity was increased to 10,125 KB. Thus, the device corresponded to the PC - 1402.

Additionally, stood on the display controller 1 Kbit (128 -byte ) memory. Of these 82 bytes are used for the display, the rest could be used freely. However, the BASIC interpreter used these 82 bytes as temporary storage, which made a display during execution of BASIC programs impossible.

PC -1402

The otherwise structurally and functionally identical PC -1402 has 10,125 KByte memory.

PC -1403

The Sharp PC -1403 has 8 Kbytes of RAM and a 24 -digit display compared to the 16 points of the PC -1401 and PC - 1402. Add text lower case letters are also additionally possible.

PC 1403h

The Sharp PC - 1403h is the top model of the 140x series. He has over the PC -1403 over 32 Kbytes of RAM.

PC -1421

The PC -1421 is a PC -1401 Version financial calculator. It differs from the PC -1401 technically only by its different ROM contents.

PC -1430

The PC -1430 is a simplified and cheaper version of the PC - 1401. The display and - apart from the smaller number of keys - the housing are the same, but there is no calculator mode ( expected in BASIC direct mode ), the functional is lower and the memory with 2 kB smaller.

PC -1450

This version offers the use of interchangeable RAM cards: CE - 211M ( 3,070 bytes = 4 kB / Standard ), CE - 201M ( 7166 byte = 8 Kbytes ) or CE - 202M ( 15358 bytes = 16 kilobytes ).

Interface

An interface peripheral devices can be connected, including thermal printers ( eg CE - 126P ), plotter, or an interface for connecting a data recorder (basically an ordinary cassette recorder ). The direct connection between two Pocket computers for data transfer is possible.

Pin Assignment

The table column direction indicates the direction of the signal. All information is subject to:

Pin | direction | Availability ----------------------   ---- ---------- ------------- | On SHARP POCKET COM ...    1 |? |? 1 - | - -----------------    2 | --- | Vcc ( 6 V) 2 - | | | |    3 | --- | Ground ( 0V) GND 3 - | - | > CSAVE |    4 | out | Busy 4 - | off | __    5 | out | Data out 5 - | -----------    6 | in | CLOAD → 6 - |    7 | out | CSAVE ← 7 - | --- --- ---    8 | in | in Data 8 - | --- --- -    9 | in | Ack 9 - | --- --- -   10 | --- | n.c. 10 - | --- ---   11 | --- | n.c. 11 - | --- -                                          | --- BASIC

The BASIC had quite a few differences to the usual BASIC dialects on:

• There were only 13-digit floating point (8 bytes), not integers.
• Variables with a letter were firmly applied and could only either floating-point or string values ​​take up to 7 characters. A and A $ could not be used simultaneously.
• RUN did not delete the variables with a letter.
• GOTO and GOSUB also went with labels and calculated expressions instead of line numbers (GOTO " A").
• There was at the derived from the PC -1401 models no lowercase, but the PC -1403 and -1450
• Array had (!) Be created explicitly (DIM AR (100 ) ). There were only two-dimensional arrays possible.
• Strings have been created statically. You had to specify when you create the length.
• Program lines could be up to 79 tokens long. Keywords were summarized in the first edit and then could no longer edit yourself.
• Extensive math commands ( up to hyperbolic ): sin, sinh, cos, cosh, tan, tanh, asin, acos, atan, asinh, acosh, atanh, ln, log, exp, ten, ...

Machine language

When not documented in the manual Extra can see the computer in machine language program (using PEEK, POKE and CALL and using routines of the operating system ), so that one can attain on the external interface, among others direct access. This makes it possible to use the calculator for measuring and control engineering applications or to couple it to other computers or devices (eg via RS -232). Individual pixels of the display can be controlled via machine language so that, for example, simple graphical games are possible. The mid to late 1980s, extensive literature has been published on this topic.

Brief introduction to the structure of the CPU: The processor of the PC -1401 is an 8 -bit processor with a clock frequency of 576 kHz. Commands always take a multiple of 3 cycles, so that one can speak of a cycle frequency of 192 kHz. Commands take a minimum of 2 cycles ( 6 cycles ), there are quite complex commands, which can be up to 769 bytes long.

The processor has two address spaces:

• ( Used 96 bytes ) 7- bit addresses for data, stack and I / O
• 16 -bit addresses for programs and data ( 8 KB of which are located in an internal ROM, 56 Kbytes can be extended by external memory).

The processor has two 8- bit accumulators (A and B ), two counting registers ( I and J), three address registers for the 8-bit address range (P, Q, and the stack pointer R) and three address registers for 16-bit addresses, (X, Y, DP). The registers A, B, I, J, X and Y will be mapped on the internal 7-bit memory again. There are some shortcuts ( load P with 6- bit value and CALL to 13 -bit address). Special features are BCD commands that add long BCD numbers with one machine instruction, subtract or move bit by 4. Furthermore, a multi -branch instruction allowed the call to a sub-function in response to an 8-bit value. Normally you need in large amounts of machine instructions.

In PC -1401 processor with 2 x 2 KByte static RAM, an LCD display with 128 bytes of RAM and 32 KB external ROM is ( are, however, only ~ used by the 25 KByte) expanded. In the successors larger RAM modules are installed.

Successor

The successor to the PC - 1401 PC - 1403.

Specifications

• Programmable Calculators
• Calculators Sharp