Intel 80219 specifications Debug Unit Synchronization with the Txrxctrl Register

Intel® 80219 General Purpose PCI Processor

Core Errata

3.Undefined Data Processing-‘like’ Instructions are Interpreted as an MSR Instruction

Problem:				The instruction decode allows undefined opcodes, which look similar to the MSR (Move to Status
				register from an ARM register) instruction, to be interpreted as an MSR instruction. The
				mis-decoded MSR instruction also adds a SUBNV PC,0x4 to the instruction flow.
Workaround:				Do not use undefined opcodes of this form:
31	30	29	28	27	26	25	24	23	22	21	20	19	18	17	16	15	14	13	12	11	10	9	8	7	6	5	4	3	2	1	0
-	-	-	-	0	0	0	1	0	-	1	0	-	-	-	-	-	-	-	-	-	-	-	-	0	0	1	0	-	-	-	-
-	-	-	-	0	0	0	1	0	-	1	0	-	-	-	-	-	-	-	-	-	-	-	-	0	1	0	0	-	-	-	-
-	-	-	-	0	0	0	1	0	-	1	0	-	-	-	-	-	-	-	-	-	-	-	-	0	1	1	0	-	-	-	-

Status: NoFix.

4.Debug Unit Synchronization with the TXRXCTRL Register

Problem:	The RX bit in the TXRXCTRL (TX/RX Control) register comes from the JTAG clock domain to
	the core clock domain, and several cycles are needed for the register in the core clock domain to
	update. During this time, a debugger, which is running a fast JTAG clock relative to the core clock,
	may read the bit before it updates in the register, thus reading the old value.
Workaround:	The JTAG clock should be slower than the core clock.
Status:	NoFix.

5.Extra Circuitry Is Not JTAG Boundary Scan Compliant

Problem:	The IEEE 1149.1 (JTAG) specification states that, “when the HIGHZ instruction is selected, all
	system logic outputs.... shall immediately be placed in an inactive drive state”. The JTAG unit on
	the core creates an internal ‘float’ signal, which is driven to the I/O pads. This signal is derived
	from the HIGHZ instruction; however, the HIGHZ instruction gets flopped by a rising edge of
	TCK first, before it is able to ‘float’ the pads. This is in violation of the JTAG specification, specif-
	ically the term “immediately”. It is possible for TCK to stop after the HIGHZ instruction is loaded
	and thus the pads may never ‘float’.
Workaround:	Do not stop the JTAG clock (TCK).
Status:	NoFix.

14 Specification Update