From e83ad3eb4184e66ae1cb31ea278f0580eb01a7b4 Mon Sep 17 00:00:00 2001 From: Jeff Parsons Date: Wed, 29 Nov 2017 23:56:53 -0800 Subject: [PATCH] Updated TI-55 blog post --- ...17-11-29-the-ti-55-programmable-calculator.md | 16 ++++++++++------ 1 file changed, 10 insertions(+), 6 deletions(-) diff --git a/_posts/2017-11-29-the-ti-55-programmable-calculator.md b/_posts/2017-11-29-the-ti-55-programmable-calculator.md index fe9db7dfd5..a3ad41cf4a 100644 --- a/_posts/2017-11-29-the-ti-55-programmable-calculator.md +++ b/_posts/2017-11-29-the-ti-55-programmable-calculator.md @@ -523,7 +523,6 @@ styles: Building on the PCjs [TI-57 Programmable Calculator](/blog/2017/11/10/) emulator, I'm happy to report that PCjs can also emulate the [TI-55 Programmable Calculator](/devices/ti55/) now. - You can see both in operation [below](#pcjs-ti-55-and-ti-57-emulators). Both calculators used the same basic chip. In the TI-57, the chip was designated "TMC1501", and in the TI-55, @@ -537,11 +536,16 @@ sold at the same list price. All I know is that both were introduced in 1977 an was $79.95. I have no information on the TI-55 list price. It's possible that the TI-55 was produced first, and then programmers at Texas Instruments were able to optimize -the ROM, increasing the number of programming steps from 32 to 50, which they then marketed as the slightly more -powerful TI-57. However, that's pure speculation on my part. It's also possible that they decided up front to -create several devices with the same hardware, providing different capabilities to different audiences, and possibly -at different price points. The fact that the TI-55 uses a chip with a higher designation ("1503") than the TI-57 -("1501") is also difficult to reconcile. +the ROM, increasing the number of programming steps from 32 to 50 and adding support for loops and conditionals, which +they then marketed as the slightly more powerful TI-57. However, that's pure speculation on my part. It's more +likely that they decided up front to create several devices with the same hardware, providing different capabilities +to different audiences, and possibly at different price points. + +Also, the fact that the TI-55 uses a chip with a higher designation ("1503") than the TI-57 ("1501") suggests that the +TI-55 may have been finished *after* the TI-57, and that the lower model number was simply a reflection of its more +limited programmability. Finally, Sean Riddle points out that since the TI-55 and TI-57 produce different results for +the "[Calculator Forensics](http://www.rskey.org/~mwsebastian/miscprj/models.htm)" test, the ROMs may have even been +developed by different teams at Texas Instruments. It may be worth undertaking a detailed comparison of the [TI-55 ROM](/devices/ti55/rom/) and [TI-57 ROM](/devices/ti57/rom/) at some point, because the TI-57 has fewer built-in functions, as evidenced by