Category:84PCE:General Hardware Information - Revision history

MicahSuess: Fixed Measurements

2022-05-04T16:41:20Z

Fixed Measurements

2022-05-04T16:37:18Z

Added Measurements for TI84 Plus CE

2021-12-09T19:35:00Z

Changed reset length threshold

2021-12-09T07:35:59Z

Reset button behavior

2020-07-20T01:12:53Z

2020-07-20T01:09:53Z

2020-04-18T15:58:04Z

Update for new stuff

2015-04-11T01:28:57Z

2015-04-02T22:33:47Z

2015-04-02T17:24:29Z

Adding PL111 doc links

@@ Line 31: / Line 31: @@
 ** If charging via USB, a long press behaves exactly like a short press.
 *TI-84 Plus CE measurements
-[[File:TI84PlusCEMeasurements.png]]
+[[File:TI84PlusCEMeasurements.png|800px|thumb|left|Measurements of TI-84 Plus CE]]

← Older revision		Revision as of 16:37, 4 May 2022
Line 30:		Line 30:
	** Holding reset for longer than about 1.5 seconds results in the calculator turning off if it was on; regardless of revision, RAM is cleared.		** Holding reset for longer than about 1.5 seconds results in the calculator turning off if it was on; regardless of revision, RAM is cleared.
	** If charging via USB, a long press behaves exactly like a short press.		** If charging via USB, a long press behaves exactly like a short press.
		+	*TI-84 Plus CE measurements
		+	[[File:TI84PlusCEMeasurements.png]]

@@ Line 27: / Line 27: @@
 * USB IP is the Faraday FOTG210
 * The reset button on the back resets the CPU, but may not always reset RAM
-** Briefly pressing reset results in the calculator turning on if it was off. On revisions before M, the boot code always clears RAM, while on revision M or later, the boot code does not clear RAM, but the OS might under some circumstances. This is the same behavior as RST 00.
+** Briefly pressing reset (for shorter than about 1.5 seconds) results in the calculator turning on if it was off. On revisions before M, the boot code always clears RAM, while on revision M or later, the boot code does not clear RAM, but the OS might under some circumstances. This is the same behavior as RST 00.
-** Holding reset for longer (5 seconds works) results in the calculator turning off if it was on; regardless of revision, RAM is cleared.
+** Holding reset for longer than about 1.5 seconds results in the calculator turning off if it was on; regardless of revision, RAM is cleared.
 ** If charging via USB, a long press behaves exactly like a short press.

← Older revision		Revision as of 07:35, 9 December 2021
Line 26:		Line 26:
	** VRAM is executable		** VRAM is executable
	* USB IP is the Faraday FOTG210		* USB IP is the Faraday FOTG210
		+	* The reset button on the back resets the CPU, but may not always reset RAM
		+	** Briefly pressing reset results in the calculator turning on if it was off. On revisions before M, the boot code always clears RAM, while on revision M or later, the boot code does not clear RAM, but the OS might under some circumstances. This is the same behavior as RST 00.
		+	** Holding reset for longer (5 seconds works) results in the calculator turning off if it was on; regardless of revision, RAM is cleared.
		+	** If charging via USB, a long press behaves exactly like a short press.

@@ Line 11: / Line 11: @@
 * 256 K main RAM
 * Memory-mapped LCD
-** 153600 bytes of "VRAM" (actually just RAM) confirmed, unknown if more exists
+** 153600 bytes of "VRAM" (actually just RAM) confirmed
 ** Possibly an ARM Primecell PL111[http://infocenter.arm.com/help/index.jsp?topic=/com.arm.doc.ddi0293c/index.html <nowiki>[HTML]</nowiki>][http://infocenter.arm.com/help/topic/com.arm.doc.ddi0293c/DDI0293.pdf <nowiki>[PDF]</nowiki>]
 * French version (TI-83 Premium CE), and other european versions (TI-84 Plus CE-T), have an LED on top for exams

@@ Line 1: / Line 1: @@
-The TI-84 Plus CE and TI-83 Premium are two models new in 2015. The former is for the USA region (maybe all of North American?) and the latter is for France. The hardware is virtually identical between the two models.
+The TI-84 Plus CE and TI-83 Premium are two models new in 2015. The former is for the USA region (maybe all of North American?) and the latter is for France. The hardware is virtually identical between the two models. In 2019, a new revision beginning with revision M was introduced, using a cached serial flash chip and optionally featuring an [[84PCE:Ports:E000|ARM coprocessor]] for running Python programs.
 Known hardware facts:
 * eZ80 CPU
 ** Physical clock speed believed to be 48 MHz
-** Effective clock speed between 12-15 MHz
+** CPU performance is severely constrained by wait states for accessing RAM and flash
-** CPU might be clocked faster but have a lot of wait states
+** On devices manufactured before revision M, the effective clock is speed between 8-16 MHz depending on ratio of RAM to flash accesses
 * 4 MB flash chip
 ** Bottom-boot organization this time

@@ Line 16: / Line 16: @@
 ** OUT causes a reset
 ** IN produces a constant value
-*** Rather, ports are now memory mapped to certain RAM addresses
+* There is memory-mapped I/O, starting at E00000. Most port ranges have a mapped address, and RAM programs are allowed to use the memory-mapped I/O.
-*** However, ports controlling items such as the testing LED remain off-limits, for good reasons.
+** The 00xx range of ports is not mapped. This range includes permissions control, flash control, the testing LED, NMI control, and possibly master power management.
 * Flash starts at $000000
 ** There is also still a flash unlock sequence